KR102649991B1 - Method and apparatus for performing field height measurements - Google Patents

Abstract

In an improved method and device for evaluating a post-tensioning tendon, the device uses a positioning head that is positioned relative to the anchor directly within the pocket without contact with the wedge as the device is seated on the tendon. From this position, the device evaluates the tendon by marking, measuring the tendon and/or determining its position with improved reliability and precision.

Description

Method and apparatus for performing field height measurements

Priority of related applications

This application claims the benefit of U.S. Provisional Patent Application No. 62/709,458, filed January 19, 2018, the entirety of which is incorporated herein by reference.

Technology field

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

Post-tensioned structures are a method of strengthening concrete with steel cables. Reinforced concrete is a composite material that has greater strength against shear forces than conventional concrete, and can be made even stronger when the steel reinforcement is stressed in a way that counteracts the expected building loads.

In post-tensioned structures, relaxed steel tendons are installed into the concrete casting before the concrete is poured. Post-tensioning tendons are surrounded by a grease-filled plastic shell that is tightly wrapped or molded around the tendon to prevent corrosion and anchoring to the concrete. The tendon is free to move laterally within the shell until both ends of the tendon are secured to the anchors. The sheathed tendons are positioned or secured within the preformed concrete casting area at positions and geometries designed to apply the required force after the concrete has solidified and the tendons have been tensioned. These tendons are typically placed to distribute compressive forces within the structure, prevent cracking of the structure, and offset any loads expected to be applied to the structure.

One end of the tendon may be installed into an anchor fixed in a cast form so that the tendon does not exceed the concrete casting area, and the end thus fixed is called a “dead end”. The tendon is installed in the anchor by installing a plurality of semiconical gripping devices called "wedges" around the tendon and around the seat within the anchor. When the appropriate gauge pressure is applied, the wedge is driven into the anchor.

Alternatively, initially, the ends of the tendons may be left with 'tails' extending beyond the casting form and passing through the anchors for later tensioning, these ends being called "live ends" or It is called a “stressing end.” Longer tendons will often have both ends that are either live ends or stressed ends.

Once the concrete is poured, the sheathed tendons within the cast form are completely surrounded by concrete, with only the live end tails exposed. The anchor is cast into the concrete with a portion of the outer surface exposed inside a "pocket" of negative space created by a plastic pocket former installed on the outer surface of the concrete structure and is mostly surrounded by concrete. The tails of the live ends of the tendons extend from the concrete structure. Once the concrete has set, the cast form and pocket formers are removed and the grease is cleaned from the exposed tendons in preparation for the marking process (described below). The stressing end is “pre-set” around the tendon with the wedge positioned partially within the anchor. When sufficient tension is applied, the pre-positioned wedge is secured within the anchor during tensioning and is fully seated within the anchor. Until the wedge is secured, the wedge may partially extend from the anchor and then extend out of the anchor once fully seated.

After the concrete has been placed to acceptable strength, the required tension, measured in kips, is applied to the tendons. This is typically accomplished by a hydraulic jack, interchangeably referred to as a “jack” or “ram”. There are a number of available jacks commercially available, such as the device disclosed in U.S. Patent No. 4,805,877. The tendons may be "prestressed" with a partial load (typically 30%) within 24 to 72 hours after placement, or the tendons may be fully tensioned after the concrete has set for 7 to 10 days or a specified minimum concrete strength has been achieved. can be approved. The ram fits the nosepiece into the pocket and grips the cable with its teeth. The ram loads the tendon with the required force (approximately 33 Kips) by pulling the gripped tendon against a wedge positioned within the anchor. The ram pressurizes the wedge, which is pushed forward into the anchor. The jack applies the required amount of force as measured (in kips) on a recently calibrated meter or gauge. Ideally, this measured amount of force is transferred to the tendon within the concrete as the tendon attempts to relax.

However, for a variety of reasons, the ram's gauge does not reliably indicate the force transmitted to the tendon. These reasons include: seating loss; creep; anchor deformation; Improper gauge calibration; Damaged tendons; Defective tendon material; Unusual amounts of friction that may be caused by anchoring or insufficient seating into the concrete; and human error. Because of these and other hazards, field elongation measurements have become a standard quality control process and are required by professional industry organizations such as the Post Tensioning Institute.

Field elongation measurements are generally performed as follows. Before tensioning, reference marks are made on the tendon 'tail' at each 'live end' outside the pocket area. These marks are made by placing a guide, usually a 2 x 4 board, against the outer surface of the concrete ensuring that the mark is located transverse to the point where the ram will grip the tendon. Using the guide as a reference, marks are made on the tendon with spray paint or other methods. Once these reference marks are made and the wedge is pre-positioned within the anchor, the ram applies the required amount of tension to the tendon. This displaces the mark from its initial position by a distance equal to the elongation of the tendon. The ram is then removed, a guide of the same length, preferably the same length as that which made the initial mark, is positioned against the surface of the concrete and the distance from the edge of the guide to the reference mark is measured with an L-square ruler. do.

The formula for calculating the theoretical elongation of the tendon material is well known in the art. Third party height measurements are performed and checked against theoretical values. Deviations from theoretical values may indicate that an insufficient amount of tension has been applied to the tendon or that the tendon is damaged or defective. If there is a discrepancy between the theoretical value (typically 0.078" per foot of tendon) and the observed value and the discrepancy is greater than the acceptable threshold (typically 7% to 10%), the structural engineer will verify that the field elongation report itself is not a user error. If the report confirms that there are no transcription and measurement errors, or if discrepancies persist, the engineer may order a lift-off test or Tensioning can be pulled again to check the elongation of the tendon because the tensioning action can cause a loss of tension and because the teeth of the wedge can damage the tendon each time the tendon is pulled and the wedge is reseated. Because the process is not non-destructive to the tendon, these tests are rarely performed more than three times.

Due to the nature of post-tensioned structures, multiple tendons within the concrete structure are typically stressed at any given time. All height measurements tend to be performed at once, with the results recorded by hand on data sheets that can later be manually communicated in digital form and sent to engineers for review. Transcription errors, measurement errors, out-of-sequence reporting errors and one-off omissions are common and tension material elongation delays may occur while awaiting a second on-site visit to make clerical corrections to the elongation report before the report can be reviewed by the engineer of record. do.

The problem with current methods arises from the lack of standard guidance. Typically, the reference guide used during the marking step is different from the device used during measurement. As variations usually occur between nominally sized 2 x 4 boards, these differences may be caused by using different axes of the same guide, or by incorrectly assuming that two different guides share a common length.

Additional problems with current methods arise from imperfections or angles in the outer surface or rim of the concrete in the pocket. The rims of tendon pockets are not perfectly coplanar; some edges of the rim may be closer to or extend farther from the plane of the concrete than other edges. Accordingly, the mark created by the guide may vary depending on where the edge of the pocket guide is located.

An additional problem with the current method arises from the small interface between the flat guide and the round tendon. The interface between the paint guide and tendon is small, so clear diffusion marks occur only at the top. Grease is applied to the tendons, and if not properly cleaned, the grease can deform the marks. The risk of a mark becoming unreadable continues to increase with the time between when the mark is created and the kidney's final review.

Current testing processes are time-intensive and require site visits when errors occur or stress readjustments are required. Typically, errors are not discovered until the test team leaves the project site, often requiring a second site visit before work can proceed.

As a means of solving these and other problems of existing methods, the present invention is an improved method and apparatus for performing field extension measurements. In the present embodiment, the device is divided into a number of operating parts, referred to as devices such as 'marking device' and 'measuring device'. References to actuating parts as devices should not be construed as limiting the invention. In general, there is no need for the operating parts of the device to be implemented as physically separate devices, unless otherwise required.

Before using the device, forms, pocket cavities and grease must be cleaned and debris removed. The device includes a standardized positioning head (preferably 4 inches in length) that is positioned directly inside the pocket and around the tendon and makes multi-point magnetic contact with the anchor. The head fits across the tendon and has a channel passing through its center that rests on the tendon. The head has a recess installed in the anchor end that is pre-positioned within the anchor and designed to fit around a wedge extending partially from the anchor and prevent contact with the wedge.

The contact surface of the head is magnetically connected to the anchor at a number of points ensuring that the head runs perpendicular to the anchor and seats flush with the tendon. Once the head is in magnetic contact with the anchor and the tendon is seated against the top of the channel, the remainder of the device is aligned into the appropriate position relative to the anchor and tendon.

The marking device includes a positioning head and a marking tool. A marking device is used to create reference marks defining the transverse plane in which the tendon deviates from the lower edge of the head. Marks are made at a standardized distance (preferably 4 inches) from the anchor by any non-destructive marking means such as spray paint and shields or by fastening an identification tag or tape encoded to the tendon.

Tension is then applied to the tendon by standard means, such as a ram type device. The ram must grip or otherwise tension the tendon at a point midway to the reference mark and transverse to the anchor. When tension is applied to the tendon, the anchor and wedge settle together to prevent the tendon from loosening.

The measuring device includes a positioning head and a measuring tool. The positioning head of the measuring device is designed identically to the head of the marking device. This symmetry ensures that the measuring device is seated across the tendon within the pocket, makes coplanar contact with the anchor, and maintains the same position as the positioning head on the marking device. The subplane of the measuring device is the same as the subplane used to place the reference mark.

A preferred version of the measuring device has a positioning head connected to a spine which is in turn connected to the measuring body. In this embodiment, the spine is attached to the positioning head of the measuring device and passes through the measuring body in such a way that the body slides transversely along the spine. The bottom of this version of the measuring body has a seating channel that allows the body to rest on the tendon. While the head of the measuring device maintains contact with the anchor, the body is free to slide laterally along the tendon and spine. In operation, the body will slide along the tendon until its upper edge is just above the reference mark. In position, the measuring device determines the height by measuring the distance between the current and original positions of the reference mark.

The present invention solves a number of problems associated with conventional methods. The standardized head of the device avoids the problems associated with marking tendons from a point defined by the outer border of the pocket by directly contacting the anchor. Other post-tensioning tools interact with the pocket, but these tools are held together against an anchor and/or push against a wedge by tensioning the tendon and otherwise interacting with the wedge. A preferred version of the marking device contacts the upper half of the surface of the tendon, leaving a clear mark over at least 40% of the perimeter of the tendon, improving the small, indistinct, diffuse marks made by conventional methods.

Some versions of the measuring device include optional means for determining position for each measurement. In this version, an antenna positioned on the upper edge of the measuring body is used to determine the position of the measuring device during the measurement. The location of the measuring device may be determined by any commercially available measuring method, such as GPS or a triangulation system. This version of the measuring device will confirm the identity of the measured tendon by comparing its position at the time of measurement with the known position of the tendon. The height data is compared to the tendon identification code and stored in the measurement device. This data file may be transferred to a computer or substantially similar device and used to generate height reports that allow more accurate height measurements to be assigned to accurately identified tendons, thereby reducing a major cause of human error.

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.
1A is a rear side perspective view of an embodiment of a marking device showing the general orientation of the components of the marking device.
Figure 1B is a front side perspective view of an embodiment of a marking device showing placement around tendons.
Figure 2A is a side perspective view of an alternative embodiment of the marking device with a partial wire-frame view of the interior showing the overall orientation and placement of the parts.
Figure 2B is a side perspective view of an alternative embodiment of a marking device with a partial wire-frame view of the interior showing proper placement of the device and id-tags or tapes.
Figure 3 is a cross-sectional view of the marking device showing the placement and operation of the positioning head within the pocket.
Figure 4A is a side perspective view of the measurement device showing the overall orientation of the part in the pocket.
Figure 4b is a cross-sectional view showing proper placement and use of a measuring device.
Figure 5A is a perspective view of an optional base station for locating an alternative embodiment of a marking device.
Figure 5b is an elevation view of an optional base station shown for determining the location of an embodiment of the measurement device.

In the foregoing summary of the invention, the following detailed description, and the accompanying drawings, reference is made to specific features (including method steps) of the invention. The disclosure of the invention herein should be understood to include 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 a particular claim, that feature may also be disclosed, to the extent possible, in combination with other specific aspects and embodiments of the invention, and/or , can be used in the context of other specific aspects and embodiments of the invention, and in the invention as a whole.

As used herein, the term "comprising" and its grammatical equivalents are used to mean that other parts, components, steps, etc. are optionally present. For example, an article containing (or “comprising”) parts A, B and C may consist of (i.e. only contain) parts A, B and C, or may consist of parts A, B and C as well as one It may include other components.

Where reference is made herein to a method comprising two or more defined steps, the defined steps may be performed in any order or simultaneously (except where the context precludes such possibility), and the method includes two defined steps. It may include one or more other steps performed before any of the defined steps, or any of the defined steps (except where the context excludes such possibility).

As used herein, the term "at least" preceding a number is used to indicate the beginning of a range (which may be an upper bound or an open-ended range depending on the variable being defined) that begins with that number. For example, “at least 1” means 1 or more.

Anatomical terms are used to indicate the location of various structures, surfaces, and elements. The term "superior, cranial" refers to the portion that is close to or approaches the head of the device when the superior or uppermost portion of the device is the anchor-side contact surface. The term “inferior,” or “caudal,” refers to the part that is located away from or in a direction away from the head. The term “transverse” refers to that portion of a device or tendon that moves away from the center of the device or tendon. The most transverse part of the tendon is the extreme tail. The term “medial” refers to that portion of the device or tendon that tends toward the center of the device or tendon. The middlemost part of the tendon is at the center of the concrete structure. The terms “top,” “superior,” and/or “dorsal” refer to that portion of the device or tendon that is in the direction of the antenna, handle, display, or base station. The terms “bottom,” “bottom,” and/or “ventral” refer to that portion of the device generally away from the direction of the antenna, handle, display, or base station. The term “transverse plane” refers to the plane separating the upper and lower surfaces. The term "longitudinal" axis refers to an axis that passes through the length of an object. The term "substantially", when used to modify the similarity or identity of two or more values, features or elements, means that the substitution does not fundamentally change the initial value, feature or function of the elements as understood by those skilled in the art. , is meant to contain features or elements.

The principles of the invention and its advantages are best understood by reference to the illustrative embodiments of the apparatus shown in the accompanying drawings, where like numbers are assigned to like parts. In the following description, well-known elements are presented without detailed description so as not to unnecessarily obscure the details of the invention. In most cases, details that are unnecessary to obtain a complete understanding of the present invention have been omitted as long as they are within the scope of skill of a person of ordinary skill in the relevant art.

positioning head

A standardized positioning head (“head”) 100 is common to the operating part of the device, which is referred to as marking device 200 and measuring device 400 . 3 and 4A, the head 100 of the measuring device must be identical to the head 100 of the marking device. The positioning head of the marking device has the same part elements, geometry and dimensions as the positioning head of the measuring device and is connected to the anchor in the same way.

1A and 3, the head is of a standardized length (preferably 4 inches) ( 104 ) and includes a channel ( 108 ), a contact surface ( 101 ), one or more magnetic surfaces ( 102A ), and a wedge pocket ( 103 ). Includes. The contact surface 101 is defined as a flat surface at the uppermost part of the head. The contact surface 101 is comprised of or inserted into one or more magnetic surfaces 102A , 102B , 102C substantially on the same plane as the contact surface. The wedge pocket 103 is a depression formed in the middle of the upper end of the head-body 107 of sufficient groove depth (preferably 1/2 inch) to accommodate a set of wedges 004 that must be within the anchor. Ensure that the contact surface is in magnetic contact with the anchor without any contacting heads. As explained in the background section, a 'pre-deployment' wedge will partially extend from the anchor and may continue to protrude from the anchor after being 'locked in' to the anchor with gauge pressure; in any case, the wedge will It will be surrounded by a 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 ) disposed within the ventral surface designed to rest around a tendon ( 001 ). In this embodiment, the head-body is formed of a hard plastic that does not deform with use, but could be replaced by any substantially similar material. Once the head is in the appropriate position, the tendon is seated on top of the channel and the contact surface is in multi-point magnetic contact with the anchor 003 (see Figure 3). In this position, the contact surface will be perpendicular to the longitudinal axis of the tendon.

1B shows a channel of sufficient size and depth that it seats coaxially around the tendon 001 such that when the remainder of the channel unfolds outward, the dorsal surface of the channel contacts at least 40% of the top surface of the tendon within the channel. ( 108 ) further illustrates a preferred embodiment. As shown, the preferred embodiment has the channel continuing through the ventral surface of the cylindrical head-body, but there is nothing inherently preventing the channel from completely surrounding the head-body. As in the embodiments described below, the head is attached to a tool member, such as a marking or measuring tool. During operation, proper positioning of the head relative to the anchor and tendon ensures proper alignment of the tool member and its workpiece.

marking device

1A and 1B show one version of the marking device 200 placed within a pocket 006 of a concrete structure 002 and positioned in isolation within the pocket 006 . The marking device includes a standardized positioning head and means for non-destructively creating reference marks on the tendon. A preferred embodiment of the marking device is shown with a standardized positioning-head ( 100 ) connected to an optional handle ( 201 ) and a paint shield ( 202 ). An optional handle 201 is shown secured to the dorsal surface of the head 100 for operator convenience.

1A and 1B show the paint shield 202 attached to the head 100 such that the lower surface of the paint shield is flush with the lower surface of the head 106 . The paint shield includes a surface connected to the interface 204 of the tendon 001 and a lower surface 106 of the head designed to spray paint (not shown) directly along the lower edge of the channel of the head 108 . The paint creates a fiducial mark 205 in the transverse plane defined by the interface 204 , preferably covering at least 40% of the perimeter of the tendon within this plane, creating a large, clear fiducial mark. 1A and 1B show optional vanes attached at an inclined angle to shields 203A and 203B oriented to capture the diffused paint and apply paint directly onto the tendon.

measuring device

The measuring device includes a positioning head, a reference mark and means for determining the linear distance of the lower surface of the head. Next the positioning-head 100 and the measuring body 411 are connected by a rigid rectangular spine 401 running transversely through a rectangular path 406 in the measuring body parallel to the channel 108 of the head. 4A and 4B, which show perspective and cross-sectional views of a preferred embodiment of a measuring device 400 comprising. The spine may be formed of steel, aluminum, plastic, or any other substantially similar material that does not lose its shape. In this embodiment, the spine 401 is fixed to the lower surface 106 of the positioning-head in such a way that the spine is free to slide back and forth while preventing rotation to keep the measuring body in-line with the tendon. It passes inside an enclosed rectangular path 406 running transversely through the body 411 and passes through the rectangular path.

In this embodiment of the marking device, the lower surface 106 of the head-body is attached to the spine 401 and the measurement target 105 . The measurement target is disposed within the lower surface of the positioning head or is disposed on the same plane as the lower surface of the positioning head.

Figures 4a and 4b further show how this version of the measuring device has a “U” shaped channel (“body-seating channel”) 407 disposed within the ventral surface of the measuring body. Body-seating channel 407 is inline with the channel 108 disposed within the head 100 , has the same dorsal most point, and has a substantially similar shape. Figure 4B shows one version of the measurement body housing the eye unit 403 . 4A and 4B show how the measuring body 411 is seated on the tendon 001. The body does not rotate to remain in-line with the head, but moves transversely along the tendon and spine. During operation, the head remains magnetically connected to the anchor while the measuring body slides along the tendon.

The tool of the measuring device for measuring linear displacement, which broadly covers alternative embodiments, may use any known technique capable of measuring the distance between the upper edge of the measuring body and the reference mark 205 . A preferred version of the measuring device comprises an eye unit 403 disposed within the upper surface of the measuring body 411 . The eye unit is a device that transmits and receives signals and interprets the results to determine linear distance. The i-unit may include any number of standard measurement devices commonly known in the industry, such as commercially available time-of-flight modules.

A preferred version of the measuring body further comprises a signal processing module 404 housed within the measuring body and electronically connected to the eye unit. The signal processing module is configured to process, interpret, and manipulate data from the eye unit or other tools as presented in alternative embodiments. This version of the measuring body includes a memory for signal processing, calculations, data storage and manipulation, a display for the device for communicating with the operator ( 408 ), and a plurality of buttons for operator capture and navigation through data stored in the device's memory ( 410 ) further includes.

The optional version of the measurement device further comprises a telescoping antenna 503A extending from the upper edge 402 of the body for communication with the base station 501 . The telescoping antenna has sufficient length to reach the level of the base station set described below.

base station

5A and 5B illustrate an optional base station 501 to be used with certain versions of the measurement device to determine the position of the measurement device during measurement. In this embodiment, the base station is placed within a depression ( 005 ) cast into the concrete structure ( 002 ) and its location is recorded on a digital map. The distance between the fixed position of the base station and the tendon ( 001 ) can be calculated from the specific installation drawing on site. The base station emits and/or receives signals that can be used to measure the distance between the base station and the antenna of the measurement device 502 . When the telescoping antenna 503A of the measuring device is raised to a known height above the measuring device, preferably above the horizontal plane of the base station, the measuring device measures its position from the fixed base station.

work

The above-described device can be used in the manner described below to perform field extension measurements with improved accuracy and minimized user error.

After the concrete ( 002 ) is cast and before stress is applied to the tendon ( 001 ), the tendon is cleaned and debris is removed from the pockets. The wedge 004 is partially pre-placed around the tendon and into the anchor 003 . Next, the head of the marking device 200 is positioned within the pocket 006 , around the tendon 001 , and relative to the anchor 003 such that its contact surface 101 is coplanar with the anchor and is in multi-point magnetic contact. And, as the dorsal surface of the tendon contacts the dorsal surface of the channel of the head 108 , contact with the wedge 004 is avoided (see FIGS. 3 and 4b). The operator may need to manually lift the relaxed tendon to maximize the interface 204 between the tendon and the channel and ensure that the tendon is in the same position it will be in after being tensioned. In this position, the tendon will leave the head a nominal distance (preferably 4 inches) 104 transversely from the anchor perpendicular to the anchor itself parallel to the lower surface 106 of the head. The operator will then mark the tendon in the plane defined by the lower edge 106 of the positioning head. In a preferred embodiment, the operator will apply spray paint to the interface 204 of the tendons as described above.

A load may then be applied to the tendon 001 by conventional means, such as a hydraulic jack (not shown), as described in the background section.

The head of the measuring device 100 is positioned within the pocket 006 , around the tendon 001 , and relative to the anchor 003 such that the contact surface 101 is in multi-point magnetic contact with the anchor. As the channel of the head 108 and the seating channel of the measuring body 407 are seated and positioned on the tendon, the head is in magnetic contact with the anchor without contacting the wedge 004 surrounded by the wedge pocket 103 (Figure see 4b). With the head in place, the target 105 of the measuring device is positioned in the same transverse plane 106 as the initial reference mark made prior to stretching 106 and is positioned at the same distance from the anchor 104 .

The operator slides the measuring body 411 along the tendon until the upper edge of the measuring body 402 is directly above the reference mark, without breaking the magnetic contact between the head and the anchor. The measuring body remains in-line with the head by sliding along the spine 401 and tendon 001 maintaining a straight path 409 between the eye unit 403 and the target 105 . Once the measurement body is in place, the device will begin capturing data of the height measurement. Data capture may be initiated manually when an operator presses the capture button 410 or may be an automatic process. Captured data may be stored in the memory of the measurement device. Optionally, the measuring device collates the results by determining both the length of the kidney and the identity of the tendon being measured and storing the values as a single observation.

When performing a measurement, a preferred embodiment of the measuring device transmits a signal on a path 409 from an emitter located within an eye unit 403 on the measuring body to a target located on the head 105 , The signal is reflected back from the target to a receiver located within the eye unit. A signal processing module 404 within the measurement body determines the eye unit's distance from the target by analyzing the signal using any known technique, including time-of-flight calculation, phase analysis, or triangulation. The distance between the eye unit and the target 409 is equal to the length of the kidney 412 (see Figure 4A). These distance values become part of the data stored as observations captured in the device's memory.

In a preferred embodiment, the base station 501 is used to determine the position of the measuring device during measurement. This position capture is optional, but if a base station is used, it must first be coupled and placed in a fixed position, preferably within a recess placed within the concrete structure ( 002 ) and the antenna ( 503A ) of the measuring device. and must be corrected. This correction establishes a reference position from the base station and a starting point for all tendons positioned. The measuring device will determine the length of the kidney and its position with sufficient accuracy to identify the measured tendon. This optional position determination step may be performed by GPS-type satellite positioning or may be performed by interacting with a base station at a known location. 5A and 5B show a base station 501 transmitting signals to a telescoping antenna 503A placed within the upper edge of the measurement device. The antenna should extend to a known height above the edge of the concrete ( 002 ), preferably at the same height as the base station ( 501 ). The measurement device will determine the linear distance 502 to the antenna by the strength of the signal from the base station.

In this optional location step, the distance from the antenna to the base station 502 and the distance from the eye unit to the anchor 504 are compared to a digital map of the tendon's location. These digital maps may be tabular in nature, populated from field installation drawings, downloaded into the device's memory, and analyzed by a signal processing module. Each tendon to be inspected is identified and provided with a tendon identification code. Tension material identification codes are associated with locations in physical space. Upon capture, the measurement device triangulates the distance from the anchor to the base station using the observed distance from the base station ( 502 ) and the observed distance to the target ( 002 ) added to the normalized head length ( 104 ). You can. These values are compared to the values on the digital map and used to determine the tendon's identification code. The identification code is stored in memory together with the captured observation against the height measurement.

After data is captured, the measurement device can visually show the captured observations on display 408 . The measuring device continues to store additional observations in its memory, which can be transmitted to a cloud-based platform for real-time remote viewing and commenting via a computer or similar device such as a mobile phone application.

Although the invention has been described in considerable detail with reference to specific preferred versions, there are other versions possible, for example:

A further embodiment of the marking device includes a housing for pressurized spray paint connected to the lower surface of the paint shield. The ventral end of the housing has a nozzle that sprays paint onto the tendon. This embodiment includes a mechanical member that depresses the nozzle of the spray paint housing by transmitting pressure to a handle, such as a lever or tension line. This embodiment facilitates operator use by allowing the operator to remotely release paint onto the interface between the paint shield and tendon without having to bend down with one hand.

A further embodiment of the marking device would include a grip for a marker, such as a grease pencil, stamp, paint brush or other non-destructive marking member, positioned on the lower surface of the paint shield. This embodiment includes a means to press the marker against the interface between the paint shield and the tendon by transmitting pressure to a handle, such as a lever or tension line.

Additional embodiments of the marking device may further include a telescoping antenna 503B of sufficient length to reach the height of the optional base station (see FIG. 5A), a power source (not shown), and operator controls (not shown). Before use, the base station 501 must be calibrated and coupled with the antenna of the marking device to determine a reference position from the base. This embodiment will transmit a signal from the antenna to determine the marking device using commercial GPS or any standard measurement technique known in the art to identify the location of the marking device relative to the concrete structure. The operator will transmit this signal when a mark is made on the tendon. This base station embodiment will determine the tendon identification code and capture time. This data will be stored as a record that the reference mark was made with the correct marking device on the correct tendon.

An alternative embodiment of marking device 300 can be seen in FIGS. 2A and 2B. This version will further include a tagging body 301 attached to the lower surface 106 of the head 100 . The tagging body will receive a plurality of id tags or tapes 302 and will position and secure the id tags to the tendon such that the upper edge of the tag is positioned against the lower face of the head 106 to serve as a reference mark. These marks can be made before stress is applied to the tendon. This embodiment will operate by disposing the ID tag 303 from the tagging body 301 and attaching the ID tag to the tensioning member, heating element or adhesive member such that the secured tag does not have any loose material not secured to the tension member. will be fixed to the tendon material ( 001 ). The id tag is not limited to any material and can be composed of tapes, stickers or coatings. The ID tag may additionally encode location information in the form of an optically encoded pattern such as a bar code or information in the form of an inductive antenna such as RFID. Many codes of this type are known in the art and are commercially available. The upper edge of the id tag must be located at the lower edge of the head. The upper edge of the tag will act as a reference mark for the measuring device.

An alternative embodiment of the measurement device would further include a sensor 405 for reading information encoded on the id tag. The embodiment of this sensor shown in FIG. 4B is shown embedded on the ventral side of the measuring body 411 , within the channel 407 , towards the upper edge of the measuring device 402 . The sensor is electronically connected to a signal processing module. In this embodiment, the sensor is oriented to focus on the id tag when the upper edge of the measurement body is located on the upper edge of the tag 303 , as shown in FIG. 4B. The sensor may be optical for optical-type tags or may include an emitter and receiver for inductive antenna type tags. While the sensor 405 in the version of the measurement device shown in Figure 4B places the sensor on the ventral side of the measurement body, the sensor can be placed anywhere on the device. The information encoded in these tags is stored as part of the observed data when an operator initiates data capture.

Additional embodiments of sensor 405 may use the sensor to determine when the upper edge 402 of the measuring device is properly positioned over a reference mark. The sensor may be at any other location that can identify that the upper edge of the measuring device is in the appropriate position over the mark. The sensor may be optically configured to focus on a line just below the upper edge of the device. When these sensors detect differences in light reflected from the marked ( 205 ) and unmarked portions of the tendon ( 001 ), or when the device determines that it is in the appropriate position, the marking device automatically captures height and position data or reports it to the operator. will visually or audibly prompt you to initiate capture.

In a further embodiment of the measurement device, eye unit 403 may include a laser triangulation-type sensor. In this embodiment, the laser within the eye unit will emit a signal that will be reflected from the target into a collection lens adjacent to the emitter within the eye unit. A condenser lens directs light into a linear detector at a known angle. The position of the focused light received by the linear detector is interpreted by the signal processing module 404 to determine the length from the eye unit to the target. This type of range finding method is well known in the art.

A further embodiment of the measuring device sensor would include a cog or sprocket positioned within a spine passage 406 within the measuring body 411 , the teeth of which are positioned in the spine 401 as the measuring body is moved back and forth from the head. Interacts with depressions. As the tooth or sprocket rotates, an angular displacement is stored as tension in the spring or charge in the capacitor, proportional to the distance the measuring body has moved from the head. This translates into a measure of distance that can be displayed and captured. Measuring devices of this type are well known in the art and are commercially available.

Additional embodiments of the measuring device may further include means for ascertaining the horizontal level, such as a bubble level or an accelerometer.

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

A further embodiment of the measuring device replaces the rigid spine and passageway with a flexible spine for ease of use and storage.

An alternative embodiment of the measurement device would use an antenna to communicate with a commercially available satellite positioning system, such as GPS, to determine the location of the upper edge of the measurement body. These location methods can complement or replace other optional location methods. The positional data will be compared to the known location of the tendon to identify the tendon.

An alternative embodiment of the device would include one or more base stations placed into additional recesses in the concrete structure to triangulate the positions of the antennas of the measuring device. These base stations are synchronized with each other to determine the time of reception of signals transmitted by the measuring device. These times are compared to each other and used to determine the device's position. The position of the device is such that the distance between the two stations is recorded and transmitted to the measuring device to determine the final stress time and the identity of the tendon being measured.

A further embodiment of the optional base station device would include a spool type tape measure dispenser. This tape measure can be extracted from the base and used to measure the distance from the location of the base station to the antenna or upper edge of the measuring device. This can be used to verify or calibrate other measurement methods or can be observed visually by the operator and manually entered into the measurement body.

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

The above-described method and apparatus improve and provide answers to problems associated with previous methods and apparatus. The marking device ensures that all measurements are taken from the same plane by measuring from anchors and using uniform reference marks. The head prevents contact with the wedge, makes contact on the same plane as the anchor, and ensures that the tendon is properly seated in the channel. The marking device creates a much larger mark that is more resistant to bleeding and distortion by increasing the area of the interface between the tendon and the paint guide. The measurement device and method captures multiple data points and allows the data to be uploaded in real time, ensuring accuracy and greatly reducing the problem of time delays in detecting errors and height discrepancies. This allows engineers of record to immediately review reliable field extension data for real-time response. This real-time rejection or approval opens up the possibility of real-time approval of final stages (cutting, painting, capping and grouting) within hours rather than days. This dramatically reduces the time tendons, anchors and wedges are exposed to the elements, protecting the integrity of the structure.

Claims (18)

A device for positioning and evaluating post-tensioning tendons surrounded by a set of wedges pre-positioned on anchors placed within pockets of a concrete structure, comprising:
a positioning head having a head-body having a contact surface and a sub-surface;
magnet;
wedge pockets;
a channel with an upper surface; and
It includes a marking member attached to the head-body,
wherein the magnet is on the same plane as the contact surface and is configured to make multi-point contact with the anchor,
The wedge pocket is recessed at the upper side of the head-body and has a sufficient size to surround the pre-positioned wedge without the head contacting the pre-positioned wedge, and the marking member is positioned at the head of the head-body. - configured to create a non-destructive fiducial mark on the tendon at a location coplanar with the lower surface of the body,
wherein the channel passes a length of the head-body configured to rest on the tendon. According to paragraph 1,
The upper surface of the channel is concave, and the concave portion of the upper surface conforms to the shape of the tendon, such that the upper surface of the channel contacts at least 40% of a portion of the surface of the tendon within the channel. delete According to paragraph 1,
The marking member includes an ID tag having an upper edge; a tagging body that receives the ID tag and is attached to a lower surface of the head-body, wherein the tagging body is attached to the tension member such that the upper edge of the tag is on the same plane as the lower surface of the head-body. A device configured to position and secure the entirety of the identity tag. According to paragraph 1,
The marking member is a paint shield attached to the head-body, the paint shield having a lower surface substantially coplanar with a lower surface of the head-body. According to clause 5,
a handle attached to the head-body, and
A device further comprising a plurality of wings attached to the shield at an inclined angle. According to clause 5,
The device is configured such that the interface of the channel, the lower surface of the head-body and the tendon are at least 40% of the perimeter of the tendon. According to paragraph 1,
further comprising means for determining linear displacement,
The device is connected to the head-body. According to clause 8,
a spine attached to the lower surface of the head-body; and
further comprising a measurement-body with an upper edge,
The measuring body is attached to means for determining a linear displacement and is attached to the spine so that the measuring body is freely movable transversely. According to clause 9,
the spine is a ridged rectangular shaft, the measuring body is formed to include a rectangular path and a body-seating channel, the rectangular path running transversely through the measuring-body and configured to receive the spine, wherein the body-seating channel is inline with the channel of the head and is configured to seat on the tendon. According to clause 9,
The means for determining linear displacement is an eye unit attached to the measuring body, attached to the lower surface of the head-body and oriented to remain in-line with the eye unit as the measuring body moves along the spine. A device further comprising a target positioned on the same plane. According to clause 9,
The device according to claim 1, wherein the means for determining the linear displacement is a sensor attached to the measuring-body. According to clause 9,
display;
button; and
Further comprising a signal processing module,
The display, the button and the module are attached to the measure-body. According to clause 13,
an antenna attached to the measuring body,
means for determining the physical location of the antenna, and
The apparatus further comprising a digital map containing the physical location of the anchor. According to clause 14,
means for determining the physical location of the antenna comprises a base station in communication with the antenna,
wherein the base station is placed within a depression of the concrete structure at a location recorded in the digital map. 1. A method of performing field elongation measurements of a post-tensioned tendon surrounded by a set of wedges and anchors placed within pockets of a concrete structure, comprising:
Preliminary placement of the wedge into the anchor;
marking the tendon with a non-destructive marking device positioned within the pocket of the structure such that the marking device is in multi-point magnetic contact with the anchor and seats on the tendon without contact with the pre-positioned wedge;
applying tension to the tendon; and
and measuring the tendon with a measuring device positioned within the pocket of the structure such that the marking device is in multi-point magnetic contact with the anchor and is seated on the tendon without contact with the pre-positioned wedge. 1. A method of performing field elongation measurements of a post-tensioned tendon surrounded by a set of wedges pre-positioned at anchors within pockets placed in a concrete structure, comprising:
creating a mark on the tendon by a non-destructive marking member of a measuring device;
Determining the position of the antenna and simultaneously measuring the elongation of the tendon using the antenna of the measuring device;
Comparing the location of the antenna with a digital map;
identifying a tendon identification code associated with the location by referring to the digital map; and
Comprising: storing the measured height compared with the tendon identification code,
wherein the marking member is positioned within the pocket of the structure such that the marking member is in multi-point magnetic contact with the anchor and is seated on the tendon without contact with the pre-positioned wedge. According to clause 17,
The method further comprising communicating said collated measurements and identification code for real-time remote review and response.