CN111918751B - Method and apparatus for performing field elongation measurements - Google Patents

Abstract

An improved method and apparatus for evaluating post-tensioned tendons, wherein the apparatus uses a locating head placed directly in a pocket and against an anchor when the apparatus is seated on a tendon , the positioning head is not in contact with the wedge. From this location, the device evaluates tendons by marking, measuring, and/or determining their location with greater reliability and accuracy.

Description

Method and apparatus for performing field elongation measurements

Priority of related applications

This application claims the benefit of US Provisional Application Serial No. 62/709,458, filed January 19, 2018, which is incorporated herein by reference in its entirety.

technical field

The present invention relates generally to post-tensioned concrete construction, and in particular to the measurement of post-tensioned tendon elongation.

Background technique

Post-tensioning construction is a method of reinforcing concrete with steel wire ropes. Reinforced concrete is a composite material that has greater strength against pure force than conventional concrete, and can even become stronger if the steel is stressed in a way to resist the expected building loads.

In post-tensioned construction, loose tendons are placed in the concrete cast before the concrete is poured. Post-tensioned tendons are enclosed in a plastic sheath that is filled with grease and tightly wrapped or cast over the tendons to protect the tendons from corrosion and to prevent anchoring to the concrete. The tendon has the freedom to move laterally within its sheath until both ends of the tendon are locked in their anchors. The location and geometry of the sheathed tendon placement or fixation within the preformed concrete placement area is designed to apply the required force after the concrete sets and the tendons are tensioned. These tendons are typically arranged to distribute compressive forces, prevent cracking, and counteract all loads expected to be placed on the structure.

One end of the tendon can be set in an anchor fixed to the pour form so that the tendon does not leave the concrete pour area; the end anchored in this way is called the "dead end". The tendons are placed in the anchor by placing a number of semi-conical gripping devices (called "wedges") around the tendon and placing them in the anchor. When the appropriate gauge pressure is applied, the wedge will be locked to the anchor.

Alternatively, the ends of tendons may initially be left with 'tails' that extend through their anchors and beyond the pour form for later tensioning; such ends are called "live ends" or "applied ends". ". Longer tendons usually have both ends as live or applied ends.

When pouring concrete, the sheathed tendons in the pouring formwork are completely surrounded by the concrete, and only the tail of the live end is exposed. The anchors are cast into, and are largely surrounded by, concrete, with a portion of their outer surface exposed within a "recess" of negative space formed by a plastic pocket formwork provided in the outer surface of the concrete structure. The tail of the live end of the tendon protrudes from the concrete structure. When the concrete has set, remove the pour and pocket formwork and wipe the grease off the exposed tendons in preparation for the marking process (discussed below). The force-applying end is "preset" with wedges that surround the tendon and partially enter the anchor. During tensioning, when sufficient tension is applied, the preset wedge will lock to the anchor and seat fully in the anchor. The wedge will not partially extend from the anchor until it is locked, and may extend to the outside of the anchor when fully seated.

After the concrete has set to an acceptable strength, load the tendons with the desired tension measured in kilopounds. This is typically accomplished with hydraulic jacks (interchangeably referred to as "jacks" or "plungers"). There are many jacks available on the market, such as the device disclosed in US Patent No. 4,805,877. The tendons can be "stressed" partially loaded (30% overall) within 24 to 72 hours after placing, or fully tensioned 7 to 10 days after the concrete has set, or otherwise to achieve the specified minimum concrete strength. The plunger fits its tip into the pocket and grips the wire with its teeth. The plunger pulls the grasped tendon against the wedge within the anchor to load the tendon with the required force (approximately 33 kilolbs). The plunger presses against the wedge that pushes the anchor forward. The amount of force (in kilopounds) required by the jack to exert on a recently calibrated meter or gauge. Ideally, this measured amount of force is transferred into the tendons, and into the concrete as the tendons try to relax.

However, there are several reasons why the plunger's gauge cannot reliably indicate the force transmitted into the tendon. These causes include, but are not limited to: loss of placement; creep; anchorage strain; improperly calibrated gauges; damaged tendons; defective tendon materials; ; and human error. Because of these and other risks, field elongation measurements have become standard quality control procedures and are required by professional and industry organizations such as the Post Tensioning Institute.

In situ elongation measurements are generally performed as follows: prior to tensioning, reference marks are made on the tendon 'tails' of each 'live end' outside the pocket area. This mark is made by placing a guide (usually a 2x4 board) on the outer face of the concrete which ensures that the mark is placed outside the point where the plunger grabs the tendon. Using the guides as a reference, mark the tendons with spray paint or other methods. Once this reference mark is made and the wedges are preset in the anchors, the plunger loads the tendons with the required amount of tension. This moves the marker from its original position a distance equal to the elongation of the tendon. Then remove the plunger, place an equal length guide (preferably the same guide used to make the initial mark) against the face of the concrete and measure the distance from the edge of the guide to the reference mark with an L-square.

Equations for calculating the theoretical elongation of tendons are well known in the art. Use third-party elongation measurements and check against theoretical values. Deviations from the theoretical value may indicate that the amount of tension applied to the tendons is insufficient, or that the tendons are damaged or defective. If there is a difference between the theoretical value (usually 0.078" per foot of tendons) and the observed value, and the difference is greater than an acceptable threshold (usually 7% to 10%), then the structural engineer will ask to revisit the site to confirm The field elongation report itself is not user error. If it is confirmed that the report is not transcribed and has no measurement errors, or the discrepancy persists, the engineer can order a peel test and/or re-stretch to confirm the elongation of the tendon in question. This test is rarely performed a third time, because the tensioning action causes a loss of tension, and because the tensioning process is not completely destructive to the tendons, due to the wedge teeth hurting each time the wedge is pulled and repositioned Rebar tendons.

Due to the nature of post-tensioning construction, there are usually a large number of tendons within a concrete structure that are stressed at any time. All elongation measurements tend to be done in one go, with the results handwritten on a data sheet, which can then be manually converted to digitized form and sent to an engineer for verification. Transcription errors, measurement errors, out-of-order reporting errors, and one-time omissions are common and cause delays in verification of tendon elongation prior to a second site visit to attempt to verify elongation reports prior to the recording engineer's verification. Document amendments.

The problems with the current method are caused by the lack of standard guides. The reference guide used during the marking step is usually different from the device used for the measurement. This difference may be due to the use of different axes of the same guide, or the erroneous belief that two different guides share a common length; as variation usually occurs between boards of nominal size 2x4.

Additional problems with current methods are due to imperfections or angles of the outer face or edge of the concrete at the cavity. The edges of tendon pockets are not completely flush, and some edges of the edges may extend closer or further from the plane of the concrete than others. Thus, the markings formed by the guides will vary depending on the edge of the pocket against which the guides are placed.

An additional problem with the current method is due to the small interface between the flat guides and the circular tendons. The interface between the paint guide and the tendon is small and will only produce a brittle scatter mark at the very top of it. The tendons are greased, and if not cleaned properly, the grease can distort the markings. The risk of the marking becoming unreadable continues to increase with the time between the time the marking is made and the final verification of elongation.

The current trial process is time-intensive and requires revisiting the site when an error occurs or a retrial is required. These errors are typically not discovered until the pilot team leaves the project site, and often require a second site visit to continue work.

SUMMARY OF THE INVENTION

As a solution to these and other problems of existing methods, the present invention is an improved method and apparatus for performing in situ elongation measurements. In its current embodiment, the device is divided into operating parts (called means, such as 'marking means' and 'measuring means'). Reference to the operating part as a device should not be construed as a limitation of the invention. It is generally not necessary to implement the operational parts of the apparatus as physically separate devices unless the context otherwise requires.

Stencils, pocket voids, and grease must be wiped away and debris removed before using the equipment. The device includes a standardized locating head (preferably 4 inches in length) that is placed directly in the pocket, surrounds the tendon, and makes multiple points of magnetic contact with the anchor. The head has a channel through the center that is mounted on and rests on the tendon. The head is provided at its anchoring end with a dimple designed to fit around and avoid contact with a wedge pre-set in the anchor and extending partially from the anchor.

The contact surface of the head is magnetically connected to the anchor at multiple points, which ensures that the head extends perpendicular to the anchor and sits flush with the tendon. When the head has been in magnetic contact with the anchors and tendons and is seated against the top of the channel, the rest of the device is aligned in exact position relative to the anchors and tendons.

The marking device includes a positioning head and a marking tool. The marking device is used to form a reference mark that defines the transverse plane of the tendon exiting the caudal edge of the head. Mark at a standard distance (preferably 4 inches) from the anchor by any non-destructive marking method, such as spray paint and guards, or by attaching coded identification tags or tape to the tendons.

Tension is then applied to the tendons by standard means, such as plunger-type means. The plunger must grab or apply tension to the tendon at a point on the inside of the reference mark and outside of the anchor. Once tension is applied to the tendons, the anchors and wedges are placed together to prevent the tendons from loosening.

The measuring device includes a positioning head and a measuring tool. The positioning head of the measuring device is designed to be identical to the head of the marking device. This symmetry ensures that the measuring device rests on the tendon, enters the pocket, is in flush contact with the anchor, and remains in the same position as the positioning head on the marking device. The caudal plane of the measuring device is the same as the caudal plane used to set the reference marks.

A preferred version of the measurement device has a positioning head connected to a spine member, which in turn is connected to the measurement body. In this embodiment, the spine member is attached to the positioning head of the measurement device and passes through the measurement body in a manner that allows the body to slide laterally along the spine member. This version of the measuring body has a seating channel at the bottom which allows the measuring body to rest on the tendons. When the head of the measuring device remains in contact with the anchor, the body has a degree of freedom to slide laterally along the tendons and spine. During operation, the body slides along the tendon until its head edge is directly above the reference mark. Once in place, the measuring device determines the amount of elongation by measuring the distance between the current position of the reference mark and the original position.

The present invention addresses many of the problems associated with existing methods. The standardized head of the device bypasses the problems associated with marking tendons from points defined by the outer edges of the pockets by making direct contact with the anchors. Other post-tensioning tools interact with the pockets, but these either secure themselves against the anchors by applying tension to the tendons, and/or push against or otherwise interact with the wedges. A preferred version of the marking device contacts the upper half of the tendon surface, leaving a clear mark on at least 40% of the tendon's perimeter, improving the small, unclear, and diffuse markings made by existing methods.

Some versions of the measurement device include optional means to determine its position on each measurement. In these versions, the antenna located on the head-side edge of the measurement body is used to determine the position of the measurement device when the measurement is taken. The location of the measurement device can be determined by any commercially available measurement method, such as GPS or a triangulation system. This version of the measuring device will confirm the identity of the tendon being measured by comparing the location at the time of measurement with the known tendon location. The elongation data is compared with the tendon identification code and saved to the measuring device. This data file will be transferred to a computer or substantially similar device and used to generate an elongation report that links more accurate elongation dimensions to correctly identified tendons, reducing a major source of human error.

Description of drawings

For a more complete understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

1A is a rear perspective view of an embodiment of a marking device illustrating the general orientation of its components.

Figure IB is a front perspective view of an embodiment of a marking device shown placed around tendons.

2A is a side perspective view of an alternative embodiment of a marking device, with a partial wireframe view of the interior, illustrating the general orientation and placement of components.

2B is a side perspective view of an alternate embodiment of the marking device, with a partial wireframe view of the interior, illustrating proper placement of the device and identification label or tape.

Figure 3 is a cross-sectional view of the marking device showing placement and operation of the positioning head in the pocket.

4A is a side perspective view of the measurement device illustrating the general orientation of components within the pocket.

Figure 4B is a cross-sectional view illustrating proper placement and use of the measurement device.

5A is a perspective view of an alternative base station for determining the location of an alternative embodiment of a marking device.

Figure 5B is a front view of an optional base station showing the location of an embodiment of a determination measurement device.

Detailed ways

In the above summary and detailed description of the invention claimed below, as well as in the drawings, reference is made to specific features of the invention (including method steps). It is to be understood that the disclosure of the invention in this specification includes all possible combinations of these specific features. For example, where a particular feature is disclosed in the context of a particular aspect or embodiment of the invention or in the context of a particular claim, that feature may also, to the extent possible, be used in combination with other particular aspects and embodiments of the invention and/or used in the context of other specific aspects and embodiments of the invention, and in the invention in general.

The term "comprising" and its grammatical equivalents are used herein to mean that other components, components, steps, etc. are optionally present. For example, an article that "comprises" (or "which includes") components A, B, and C may include (contain only) components A, B, and C, or may include not only components A, B, and C but also one or multiple other components.

Where reference is made herein to a method comprising two or more identified steps, the identified steps can be performed in any order or concurrently (unless the context precludes this possibility), and the method may include one or more other steps before any identified step, between two identified steps, or after all identified steps (unless the context precludes this possibility).

The term "at least" followed by a number is used herein to denote the beginning of a range (which may or may not have an upper limit, depending on the variable being defined) beginning with that number. For example, "at least 1" means 1 or more than 1.

Anatomical terms are used to indicate the location of various structures, surfaces, and elements. The terms "upper" and/or "cephalic" refer to the portion near or proximate to the head of the device, wherein the upper or most cranial portion of the device is the anchor-side contact surface. The terms "under" and/or "caudally" refer to the portion facing away from the head or in a direction away from the head. The term "outside" refers to the portion of a device or tendon that moves away from the center of the device or tendon. The outermost part of the tendon is the end of the tail. The term "inside" refers to the portion of the device or tendon that tends towards the center of the device or tendon. The innermost part of the tendon is in the center of the concrete structure. The terms "top," "upper," and/or "back" refer to the portion of the device or tendon that faces the antenna, handle, display, or base station. The terms "lower," "bottom," and/or "ventral" refer to the portion of the device that is generally away from the direction of the antenna, handle, display, or base station. The term "transverse plane" describes the plane separating the cranial and caudal surfaces. The term "longitudinal" axis refers to the axis of the length of an object. When used to modify the similarity or equality of two or more values, features, or elements, the term "substantially" is meant to include similar values, features, or elements, the substitution of which does not fundamentally change the original The function of the value, feature, or element, as understood by one of ordinary skill in the relevant art.

The principles of the present invention and its advantages may be best understood by referring to the illustrative embodiments of the device depicted in the accompanying drawings, wherein like numerals refer to like parts. In the following description, well-known elements are presented without detailed description in order not to obscure the present invention in unnecessary detail. In most instances, details not necessary to obtain a full understanding of the present invention are omitted since they are within the skill of one of ordinary skill in the relevant art.

Position the head

The standardized positioning head ("head") 100 is common to the operating parts of the apparatus referred to as the marking device 200 and the measuring device 400. Referring to Figures 3 and 4A, the head 100 of the measuring device and the head 100 of the marking device must be identical. The positioning head of the marking device has the same components, geometry, dimensions and is connected to the anchor in the same way as the positioning head in the measuring device.

Referring to FIGS. 1A and 3 , the head has a standardized length 104 (preferably 4 inches) and includes a channel 108 , a contact surface 101 , one or more magnetic surfaces 102A, and a wedge pocket 103 . The contact surface 101 is defined as a flat surface at the most cranial portion of the head. The contact surface 101 consists of or has embedded one or more magnetic surfaces 102A, 102B, 102C substantially coplanar with the contact surface. The wedge pocket 103 is a pocket provided on the inside of the cephalad end of the head body 107 that has a sufficient recessed depth (preferably 1/2 inch) to allow the contact surface to make magnetic contact with the anchor without the head Not in contact with a set of wedges 004 that must be in the anchor. As stated in the Background section, the 'pre-set' wedge will extend partially out of the anchor and may continue to protrude from the anchor even after the wedge is 'locked' on the anchor with gauge pressure; In one case, the wedge will be closed by the wedge pocket without physical contact with the head (see Figure 3).

A preferred version of the head comprises a cylindrical head body 107 and a "U" shaped channel 108 provided in its ventral surface, which channel is designed to sit around tendon 001 . In this embodiment, the head body is made of hard plastic that does not deform with use, but any substantially similar material may be substituted. When the head is in the correct position, the tendons rest against the top of the channel and the contact surfaces make magnetic multi-point contact with the anchors 003 (see Figure 3). In this position, the contact surface will be perpendicular to the longitudinal axis of the tendon.

Figure IB further illustrates a preferred embodiment of a channel 108 of sufficient size and depth to be positioned coaxially around tendon 001 such that the backside surface of the channel is at least 40 degrees from the upper surface of the tendon within the channel % contact, the rest of the channel flares outward. Although the preferred embodiment has the channel shown continuously through the ventral surface of the cylindrical head body, nothing inherently prevents the channel from being completely closed by the head body. As discussed in the embodiments below, the head is attached to a tool member, such as a marking tool or a measuring tool. During operation, the correct placement of the head relative to the anchors and tendons ensures the correct alignment of the tool member and its workpiece.

marking device

FIGS. 1A and 1B individually show a version of the marking device 200 placed in a pocket 006 provided within a pocket 006 of a concrete structure 002 . Marking devices include standardized positioning heads and devices for non-destructively forming reference marks on tendons. A preferred embodiment of the marking device is shown with a standardized positioning head 100 attached to an optional handle 201 and paint shield 202 . An optional handle 201 is shown secured to the dorsal surface of the head 100 for ease of use by the operator.

FIGS. 1A and 1B show paint shield 202 attached to head 100 in such a way that the paint shield's trailing surface is coplanar with the head's trailing surface 106 . The paint shield includes a surface connected to the caudal surface 106 of the head designed to guide the spray paint (not shown) along the interface 204 of the tendon 001 and the caudal edge of the channel 108 of the head. The paint forms a reference mark 205 in the transverse plane defined by the interface 204, which preferably covers at least 40% of the perimeter of the tendon in this plane, resulting in a large and clear reference mark. FIGS. 1A and 1B show optional wings attached to the guards 203A, 203B at an oblique angle, the wings being oriented to direct paint onto tendons and capture diffused paint.

Measuring device

The measuring means include positioning the head and means for determining the linear distance between the reference mark and the caudal surface of the head. Referring next to Figures 4A and 4B, these figures show perspective and cross-sectional views of a preferred embodiment of a measurement device 400 comprising a positioning head 100 and a measurement body 411 connected by a rigid rectangular spine member 401, the spine The piece passes laterally through a rectangular passage 406 in the measurement body parallel to the channel 108 of the head. The spine member may be made of steel, aluminum, plastic, or any other substantially similar material that does not lose its shape. In this embodiment, the spine member 401 is secured in the caudal surface 106 of the positioning head and passes internally through a closed rectangular passageway 406 that passes laterally through the measurement body 411 to allow the measurement body to pass along the The freedom of the spine piece to slide back and forth, while inhibiting rotation, in order to maintain alignment with the tendon.

In this embodiment of the marking device, the caudal surface 106 of the head body is attached to the spine member 401 and the measurement target member 105 . The measurement target is disposed in or coplanar with the caudal surface of the positioning head.

Figures 4A and 4B further illustrate how this version of the measurement device has a "U" shaped channel ("body seating channel") 407 provided in the ventral surface of the measurement body. The body placement channel 407 is aligned with the channel 108 provided in the head 100, has the same dorsalmost point, and has a substantially similar shape. FIG. 4B shows a version of the measurement body housing the eye unit 403 . Figures 4A and 4B show how the measurement body 411 is placed on the tendon 001 . The body has degrees of freedom to slide laterally along the tendons and spine members without rotating so as to remain in line with the head. During operation, the head remains magnetically connected to the anchor as the measuring body slides along the tendon.

As broadly covered in alternative embodiments, the means of the measuring device for measuring linear displacement may use any known technique capable of measuring the distance between the cranial edge of the measuring body and the reference mark 205 . A preferred version of the measurement device comprises an eye unit 403 arranged in the cephalic surface of the measurement body 411 . The eye unit is a device that determines straight-line distance by transmitting and receiving signals and interpreting the results. The eye unit may incorporate any number of standard measurement devices commonly known in the industry, such as commercially available time-of-flight modules.

The preferred version of the measurement body additionally includes a signal processing module 404 electrically connected to the eye unit and housed within the measurement body. The signal processing module is adapted to process, interpret, and manipulate data from the eye unit or other tools discussed in alternative embodiments. This version of the measurement body additionally includes memory for signal processing, calculations, data storage, and manipulation, a display 408 for the device to communicate with the operator, multiplexer for the operator to capture and view data stored in the device memory button 410.

An optional version of the measuring device additionally includes a telescopic antenna 503A extending from the head-side edge 402 of the body for communicating with the base station 501 . The length of the telescoping antenna is sufficient for the base station setup discussed below.

base station

Figures 5A and 5B show an optional base station 501 that will be used in conjunction with some versions of the measuring device to determine the location of the measuring device when taking measurements. In this embodiment, the base station is placed in a pit 005 cast into the concrete structure 002, and its location is recorded in a digital map. The distance between the fixed location of the base station and the tendon 001 can be calculated from site-specific installation drawings. The base station transmits and/or receives signals that can be used to measure the distance 502 between the base station and the antenna of the measurement device. When the telescopic antenna 503A of the measuring device is raised to a known height above the measuring device (preferably the level of the base station), the measuring device measures the position of the telescopic antenna from the fixed base station.

operate

The apparatus disclosed above is used to make in situ elongation measurements with improved accuracy and minimal user error in the following manner.

After the concrete 002 is poured and before the tendons 001 are stressed, the tendons are wiped clean and the pockets are cleaned of debris. The wedges 004 are preset to surround the tendons and partially enter the anchors 003 . Next, the head of the marking device 200 is placed in the pocket 006, around the tendon 001, and against the anchor 003 so that when the backside surface of the tendon is in contact with the backside surface of the channel 108 of the head , the contact surface 101 of the head is in flush, magnetic multi-point contact with the anchor and avoids contact with the wedge 004 (see Figures 3 and 4B). The operator may need to manually lift the slack tendons to maximize the interface 204 between the tendons and the channel and to ensure that the tendons are in the same position as after tension has been loaded. In this position, the tendons will be a normalized distance 104 (preferably 4 inches) from the head, which is outside and perpendicular to the anchor, which itself is parallel to the caudal surface 106 of the head. The operator will then mark the tendons at the plane defined by the trailing edge 106 of the positioning head. In a preferred embodiment, as previously discussed, the operator applies spray paint to the interface 204 of the tendons.

The tendons 001 are then loaded by conventional means, such as by hydraulic jacks (not shown) as described in the background section.

The head of the measuring device 100 is placed in the pocket 006 around the tendon 001 and against the anchor 003 so that the contact surface 101 makes multi-point magnetic contact with the anchor. When the channel 108 of the head and the seating channel of the measuring body 407 straddle and rest on the tendon, the head is in magnetic contact with the anchor and not with the wedge 004 enclosed in the wedge pocket 103 (see Figure 4B). With the head in place, the target piece 105 of the measurement device is located in the same lateral plane 106 as the initial reference mark prior to elongation 106 and at the same distance from the anchor 104 .

Without breaking the magnetic contact between the head and the anchor, the operator slides the measurement body 411 along the tendon until the head side edge 402 of the measurement body is directly on the reference mark. As the measurement body slides along the spine member 401 and tendons 001 , the measurement body remains in line with the head, maintaining a straight path 409 between the eye unit 403 and the target member 105 . When the measuring body is in place, the device will initiate data capture of the elongation measurement. Data capture can be initiated manually when the operator presses the capture button 410, or can be an automatic process. The captured data can be saved to the memory of the measurement device. Optionally, the measuring device will determine the length of the elongation and the identity of the tendon being measured and compare the results by storing the values as a single observation.

When a measurement is performed, the preferred embodiment of the measurement device sends a signal on path 409 from a transmitter located in the eye unit 403 on the measurement body to the target 105 located on the head, and the signal is reflected by the target and returned to the located in the receiver inside the eye unit. A signal processing module 404 within the measurement body determines the distance to the eye and target by analyzing the signal using any known technique including time-of-flight calculations, phase analysis, or triangulation. The distance 409 between the eye and the target is the same as the length of the elongation 412 (see Figure 4A). This distance value becomes part of the data stored in the device's memory as captured observations.

In a preferred embodiment, the base station 501 is used to determine the location of the measuring device during the measurement. This position capture is optional, but if a base station is used, it must first be engaged and placed in a fixed position, preferably in a pit provided in the concrete structure 002, and calibrated with the antenna 503A of the measurement device. This calibration sets the reference position from the base station and the starting point of all positioned tendons. The measuring device will determine its position accurately enough to identify the tendon being measured while determining the length of the elongation. This optional positioning step can be performed by GPS-type satellite positioning or by interacting with the base station at its known location. Figures 5A and 5B show a base station 501 which transmits a signal to a telescopic antenna 503A provided in the head-side edge of the measuring device. The antenna should extend to a known height above the edge of the concrete 002, preferably the same height as the base station 501. The measuring device will determine its linear distance 502 to the antenna through the strength of the signal of the base station.

In this optional positioning step, the distance 502 of the antenna to the base station and the distance 504 of the eye unit to the anchor are compared to a digital map of the location of the tendons. This digital map can be essentially a table, populated from site-specific installation drawings, then downloaded into the unit's memory and analyzed by the signal processing module. Each tendon to be tested is identified and assigned a tendon identification number. The tendon identifiers are associated with locations in physical space. At acquisition, the measuring device can use its observed distance 502 to the base station and its observed distance to the target piece 105 plus the normalized head length 104 to triangulate the anchor's distance to the base station. This value is compared with the value in the digital map and used to determine the tendon identification code. This identification code is compared with the elongation measurement and stored in memory along with the captured observation.

After capturing the data, the measurement device may visually display the captured observations on display 408 . The measurement device will continue to store additional observations in memory, which can be output to a cloud-based platform via a computer or similar device (such as a mobile phone app) for real-time remote viewing and commenting.

Although the invention has been described in great detail with reference to certain preferred versions, other versions are possible, such as:

An additional embodiment of the marking device includes a pressurized paint spray housing attached to the aft side surface of the paint shield. The ventral end of the shell has nozzles for spraying paint onto the tendons. This embodiment includes a mechanical means for transmitting pressure applied at the handle, such as a lever or tension wire, to depress the nozzle of the paint housing. This embodiment provides ease of use for the operator by allowing him or her to release the paint remotely onto the interface between the paint shield and the tendon with one hand without bending over.

Additional embodiments of the marking device would incorporate a gripper for marking, such as a grease pencil, stamp, paintbrush, or other non-destructive marking member, on the caudal surface where the paint lays silent. This embodiment includes means for transmitting pressure applied at the handle, such as a lever or tension wire, to press the marker on the interface between the paint shield and the tendon.

Additional embodiments of the marking device would additionally include: a telescoping antenna 503B long enough to reach the height of an optional base station (see Figure 5A); a power source (not shown); and an operator control (not shown) . Before use, the base station 501 must be engaged and calibrated with the antenna of the marking device to determine the reference position from the base station. This embodiment will send a signal from its antenna to determine the marking device using commercial GPS or any standard measurement technique known in the related art to identify the location of the marking device relative to the concrete structure. The operator will send this signal when making a mark on the tendon. This embodiment of the base station will determine the tendon identification code and capture time. This data will be stored as a record that reference marks have been made at the correct tendons using the correct marking device.

Alternative embodiments of marking device 300 can be seen in Figures 2A and 2B. This version would additionally include a labelling body 301 attached to the trailing surface 106 of the head 100 . The labelling body will accommodate the plurality of identification labels or tapes 302 and will position and secure the identification labels to the tendons such that the cranial edge of the labels abuts the caudal surface 106 of the head for use as a reference mark. This marking will be done before the tendons are stressed. This embodiment would operate by placing the identification tag 303 from the tagging body 301 and securing it to the tendon 001 by tensioning members, heating elements, or adhesive members, so that the secured tag does not have any unsecured to the tendon. loose material. Identification labels are not limited to any material and may be made of tape, stickers, or coatings. The identification tag may additionally encode the location information in the form of an optical encoding pattern (such as a barcode), or the information in the form of an inductive antenna (such as an RFID). Many codes of this type are known in the relevant art and are commercially available. The cranial edge of the identification label must be placed at the caudal edge of the head. The head-side edge of the label will act as a reference mark for the measuring device.

Alternative embodiments of the measurement device would further include a sensor 405 for reading the information encoded on the identification tag. As shown in Figure 4B, an embodiment of this sensor is shown embedded on the ventral side of the measurement body 411, within the channel 407, and towards the cranial edge 402 of the measurement device. The sensor is electrically connected to the signal processing module. In this embodiment, the sensor is oriented to focus on the identification label when the head-side edge of the measurement body is placed on the head-side edge of the label 303, as shown in Figure 4B. For optical-type tags, the sensor may be optical, or may include a transmitter and receiver for sensing antenna-type tags. Although the sensor 405 in the version of the measurement device shown in Figure 4B locates the sensor on the ventral side of the measurement body, the sensor can be located anywhere on the device. When the operator initiates data capture, the information encoded in such tags will be stored as part of the observed data.

Further embodiments of the sensor 405 may use the sensor to determine when the cranial edge 402 of the measurement device is properly placed on the reference mark. The sensor may be located at any other location that enables the sensor to identify the correct position of the head-side edge of the measuring device above the marking. The sensor may be optical, adapted to focus on a line directly below the head-side edge of the device. When such a sensor detects the difference in light reflected from the marked portion 205 and the unmarked portion of the tendon 001, or otherwise determines that the device is in the correct position, the marking device will automatically capture elongation and position data , or the operator will be prompted visually or audibly to initiate capture.

In a further embodiment of the measurement device, the eye unit 403 would comprise a laser triangulation type sensor. In this embodiment, a laser within the eye unit will emit a signal that will reflect from the target and enter a collection lens within the eye unit adjacent to the emitter. The collection lens directs the light into the linear detector at a known angle. The signal processing module 404 interprets the position of the focused light received by the linear detector to determine the length of the eye unit to the target. Ranging methods of this type are well known in the art.

In an additional embodiment of the measurement device, the sensor would include a gear or sprocket located within the spine member channel 406 in the measurement body 411, the teeth of the gear or sprocket with the spine member 401 as the measurement body moves back and forth from the head dimple interaction in . When the gear or sprocket turns, the angular displacement is stored as tension in the spring, or as electric charge in the capacitor, proportional to the distance of the measuring body from the head. This is converted into a measure of distance that can be displayed and captured. These types of measurement devices are well known in the art and are commercially available.

Additional embodiments of the measuring device would further include a device to confirm that it is horizontal in a horizontal direction, such as a bubble level or an accelerometer.

A further embodiment of the measuring device uses a scale as a rectangular spine member. The ruler can be used to confirm measurements made by other means, or it can be visually observed and manually entered into the measurement body by the operator.

For ease of use and storage, additional embodiments of the measurement device replace rigid spine members and channels with telescopic spine members.

An alternative embodiment of the measurement device would use its antenna to communicate with a commercially available satellite positioning system, such as GPS, to determine the position of the head-side edge of the measurement body. This positioning method can supplement or replace other optional positioning methods. For tendon identification purposes, the location data is compared to the known locations of tendons.

An alternative embodiment of the apparatus would include one or more base stations arranged in additional pit(s) in the concrete structure to triangulate the position of the antenna of the measuring device. These base stations are synchronized with each other and determine when they receive the signal sent by the measuring device. These times are compared to each other to determine the location of the device. The location of the device, the distance between the two stations, is recorded and sent to the measurement device to determine the time of final stress and the identity of the tendon being measured.

An additional embodiment of the optional base station device would include a reel-type tape measure dispenser. This tape measure can be pulled out of the base and used to measure the distance from the base station location to the headside edge of the antenna or measuring device. This can be used to confirm or calibrate other measurement methods, or it can be visually observed and manually accessed by the operator.

Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.

The methods and apparatus disclosed above improve upon and solve the problems associated with previous methods and apparatus. Make Marking Devices Ensure all measurements are taken from the same plane by measuring from the anchor and using uniform reference marks. The head avoids contact with the wedges, makes flush contact with the anchors, and ensures that the tendons are properly seated in the channel. The marking device makes larger marks by increasing the interfacial area between the tendons and the paint guides, which are more resistant to smearing and deformation. The measurement device and method captures multiple data points, ensuring accuracy by allowing real-time upload of data, greatly reducing time delay issues in discovering errors and elongation differences. This enables engineers of record to instantly check reliable field elongation data for real-time response. This real-time rejection or approval enables real-time approval of finalizing steps (cutting, painting, capping, and grouting) to occur in hours instead of days. This protects the integrity of the structure by significantly reducing the time that tendons, anchors, and wedges are exposed to the environment.

Claims (17)

1. A device for locating and evaluating post-tensioned tendons enclosed by a set of wedges in anchors preset in pockets of concrete structures, the device comprising: a positioning head having a head body with a contact surface and a caudal surface; magnet; wedge recess; a channel having an upper surface; and make markup components, wherein the magnet is coplanar with the contact surface and is adapted for multipoint contact with the anchor, the wedge pocket is recessed into the head side of the head body and is of sufficient size to enclose the predetermined wedges, while the head is not in contact with said predetermined wedge and the passage runs through the length of the head body adapted to rest on the tendon, The marking member is attached to the head body and is adapted to form a non-destructive reference mark on the tendon at a location coplanar with the caudal surface of the head body. 2. The apparatus of claim 1, wherein the upper surface of the channel is concave, the concavity of the upper surface matching the shape of the tendon such that the upper surface of the channel is concave with the inner surface of the channel At least 40% of the tendon surfaces are in contact. 3. The apparatus of claim 1, wherein the marking member comprises: Identification label with head-side edge; a labelling body housing the identification tag, the labelling body being attached to the trailing surface of the head body; Wherein the labelling body is adapted to place and secure the entire identification label to the tendon such that the cranial edge of the label is coplanar with the caudal surface of the head body. 4. The apparatus of claim 1, wherein the marking member is a paint shield attached to the head body, the paint shield having substantially the same caudal surface as the head body. caudal surface of the face. 5. The apparatus of claim 4, further comprising: a handle attached to the head body, and Wings are attached to the shield at an oblique angle. 6. The apparatus of claim 4, wherein the apparatus is adapted such that the interface of the channel, the trailing surface of the head body and the tendon is at least 40% of the circumference of the tendon. 7. The apparatus of claim 1, further comprising means for determining linear displacement, wherein the means is attached to the head body. 8. The apparatus of claim 7, further comprising: a spine member attached to the caudal surface of the head body; and Measuring body with cranial edge; Wherein, the measurement body is attached to the device for determining linear displacement and to the spine member so that the measurement body has a degree of freedom of lateral movement. 9. The apparatus of claim 8, wherein the spine member is a ridged rectangular shaft, and the measurement body is formed to include a rectangular passageway and a body seating passageway, wherein the rectangular passageway passes laterally through the measurement The body is adapted to receive the spine member, and the body seating channel is aligned with the head channel and adapted to seat on the tendon. 10. The apparatus of claim 8, wherein the means for determining linear displacement is an eye unit attached to the measurement body, and further comprising an eye unit attached to the caudal surface of the head body and connected to the caudal surface of the head body. A target with coplanar caudal surfaces oriented to remain in line with the eye unit as the measurement body moves along the spine. 11. The apparatus of claim 8, wherein the means for determining linear displacement is a sensor attached to the measurement body. 12. The apparatus of claim 8, further comprising: monitor; button; and the signal processing module, Wherein, the display, the button, and the module are attached to the measurement body. 13. The apparatus of claim 12, further comprising: an antenna attached to the measurement body, means for determining the physical location of the antenna, and Include a digital map of the anchor's physical location. 14. The apparatus of claim 13, wherein the means for determining the physical location of the antenna comprises a base station in communication with the antenna, wherein the base station is positioned in a pit in the concrete structure within the digital at the location recorded on the map. 15. A method of performing in-situ elongation measurements of post-tensioned tendons enclosed by a set of wedges and anchors disposed within pockets of a concrete structure, the method comprising the steps of: The wedges are preset in the anchor, The tendon is marked with a non-destructive marking device positioned in the recess of the structure so that the marking device is in magnetic multi-point contact with the anchor and rests on the tendon without contacting the pre-set wedges contact; apply tension to the tendon; and The tendons are measured with measuring devices positioned in pockets of the structure such that the marking device is in magnetic multipoint contact with the anchors and rests on the tendons without contacting the preset wedges. 16. A method of performing in-situ elongation measurements of post-tensioned tendons enclosed by a set of wedges in anchors preset in pockets provided in a concrete structure, the method comprising The following steps: measuring the elongation of the tendon with a measuring device including an antenna, and at the same time determining the position of the antenna; compare the location of the antenna with a digital map; identifying the tendon identification code associated with the location by reference to the digital map; and Stores the measured elongation against this tendon ID. 17. The method of claim 16, further comprising the step of transmitting the contrasted measured elongation and identification code to enable real-time remote verification and response.

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