1. Basis for compilation.
Urumqi Wanda Plaza Shopping Center - Mandarin Hotel Construction Drawings;
Construction Safety Inspection Standard" JGJ59-2011;
Unified Standard for Acceptance of Construction Quality of Construction Projects GB50300-2013;
Fifth Edition of Building Construction Manual;
Technical specification for the application of anchors, clamps and connectors for prestressed tendons" JGJ85-2010;
Steel strand for prestressed concrete》GB T5224-2003;
Prestressed tendon anchors, clamps and connectors" (GB T14370-2007).
Metal corrugated pipe for prestressed concrete" (JG225-2007).
Code for Prestressed Construction of Construction Projects (CECS180-2005).
Code for seismic design of prestressed concrete structures (JGJ140-2004).
Code for Construction Quality Acceptance of Concrete Structure Engineering (GB50204-2002) 2011 Edition.
Current national and local norms, standards and procedures;
Urumqi Wanda project construction organization design.
First, the general situation of the project.
Urumqi Wanda Plaza Shopping Center - Mandarin Hotel podium house surface layer between the 2-1 axis to 2-1 5 axis between a total of 9 prestressed beams, the post-tensioning method is used to bond prestressed, the prestressed concrete strength grade is C40, the design adopts two-end tensioning, in which the position of the front façade and the tension end are on the frame column, and the recessed tension end is used when the back façade and the tension end is on the beam. The cross-section of the prestressed beam is 550mm 1900mm, of which six lengths are 38900mm, two lengths are 45450mm, and one length is 43950mm (the length is the axis spacing of the beam ends). Two 85 metal bellows are provided in the beam, and each bellows in the six beams is 14 s152. Low relaxation (class I relaxation) steel strand, 11 s15 in each bellows in three beams2. Low relaxation (class I relaxation) steel strand. The strength standard value is FPTK=1860MPa;fpy=1320mpa。The specific parameters and node practices of the prestressed beam are detailed in Urumqi Wanda Plaza Shopping Center - Mandarin Hotel Jieshi-17 and Jieshi-22.
Engineering preparation. 3.1. Technical preparation.
3.1.1. After receiving the drawings, the technical department shall organize the foreman, quality, re-sampling, pay-off and prestressing professional construction team to jointly review the drawings, and read the construction drawings, design requirements and construction practices in detail. The old and new drawings should be listed in detail, including the name, number, date of receipt, and number of copies, and the drawings should be marked with a red pen on the catalog and drawings to avoid the use of scrapped drawings.
3.1.2. The design disclosure record and design change and negotiation should be sorted out and issued to the functional departments in a timely manner, and each department must mark the change to the drawings on the construction drawings to avoid errors in the use of drawings.
3.2. Preparation of construction personnel.
3.2.1. The project needs to be equipped with 6 management personnel, including 1 technician, 1 quality inspector, 2 safety officers and 2 foremen. It is necessary to configure 10 prestressed pipeline installers and 8 tensioning technology and cooperation personnel.
3.2.2. According to the start date and labor demand plan, organize workers to enter the site and arrange the workers' lives. The erection and installation of water and electricity pipelines have been completed, which can meet the water and electricity needs of engineering construction and project management, and the life of construction personnel.
3.2.3. Do a good job in the safety, quality, fire prevention, civilized construction and other education work of construction personnel, conduct pre-job training, and must hold certificates for key technical types of work, and carry out secondary safety technology disclosure according to regulations, including: construction schedule;Various safety, technical and quality assurance measures;Quality standards and acceptance specifications;design changes and technical approvals, etc. When necessary, on-site demonstrations will be conducted, and at the same time, various rules and regulations will be improved, and education on compliance with laws and regulations will be strengthened.
Prepare the machine
The configuration of construction machinery and tools is as follows (Table 2).
Note: The tensioning equipment is calibrated before use, and it is calibrated once in the construction not more than half a year.
Preparation of materials
1) Concrete: The concrete strength grade of the prestressed beam is C40.
2) Prestressed steel bar: The bonded prestressed steel used in the project is a low relaxation and high strength prestressed steel strand, which should comply with the regulations, and the diameter of a single steel strand is 152. The area of the steel strand A = 140mm2 The standard tension of the steel strand is RBY = 1860MPa Modulus of elasticity EY=195×105mpa。
3) Anchorage: anchorage, fixture should meet the requirements of the standard "anchors, fixtures and connectors for prestressed tendons" (GB T14370), tensile anchors are selected 15-14 type, and their performance should meet the requirements of class 1 anchors.
3.5. Environment preparation
1) The road of the whole construction site is unobstructed. Temporary substation box, primary and secondary distribution box are operating normally. All kinds of construction materials have been arranged in place according to the requirements.
2) All kinds of propaganda and warning signs have been erected and protected in place.
3.6. Construction schedule
Since October 14, 2014, the prestressed professional construction team should enter the site to start the pre-embedding work of prestressed steel strand and metal corrugated pipe, and the work will be completed on October 18, 2014. When the concrete pouring of the prestressed beam is completed and the concrete strength grade reaches 90% and the climatic conditions meet the tensile conditions, the tensile work of the prestressed steel bar is started.
First, the main construction process.
Fourth, the main sub-project construction methods.
5.1. The spiral pipe is laid and fixed
1) The spiral pipe should be fixed according to the line type required by the design, and the two meters before and after the reverse bending point of the metal bellows should be positioned with a 500mm spacing of a well-shaped steel bracket or hanger, and the rest of the positions should be positioned with a 1000mm spacing of a well-shaped steel bracket or hanger, and the bracket or hanger should be fixed firmly with the non-prestressed steel bars of the components. The tic-tac-toe steel bracket and hanger are made of 10 steel bars.
1) For the multi-wave curve beam in the continuous structure, and the height difference is large, the exhaust hole (water pipe) should be set at each peak and peak valley of the curve;For long straight channels, exhaust holes (water pipes) should be installed every 12 to 15 m or so.
2) The connection of the spiral pipe can be made of the same type of spiral piece that is one size larger, and the length of the joint pipe is 300mm
3) The horn tube at the tension end should be fixed with screws and templates, and the number of fastening screws should not be less than 3.
4) There are two ways to connect the spiral tube and the tension end horn tube: one is to penetrate the spiral tube into the hole of the tension end horn tube, and extend to the tension end face of the horn tube, and wrap and seal the gap between the spiral tube and the bell mouth with sealing tapeThe other is that the spiral tube does not extend into the horn pipe orifice, the spiral tube is sleeved into the end of the horn tube, and then the spiral tube and the horn tube gap are wound and sealed with sealing tape. According to the actual situation of the site, you can choose it.
5) The spiral pipe should be connected from one end in turn, and repeated bending should be avoided as much as possible during the penetration process to prevent the pipe wall from cracking, and at the same time, the welding spark should be prevented from burning the pipe wall.
6) According to the actual situation of this project, the steel bar at the protruding end of the connection between the spiral pipe and the anchor backing plate (bell mouth) is too dense to install the spiral bar normally. Therefore, appropriately increase the beam (column) reinforcement spacing, and the protruding end is strengthened by using 10 steel bars combined into a reinforcement mesh, and the mesh hole spacing shall not be less than 100mm, and the mesh shall not be less than 5 layers.
This project adopts OVM circular clamp anchorage, which is shown in the figure below.
5.2. Prestressed steel bar blanking, processing and bunching
1) The blanking site should be lined with square wood or laid with woven cloth, and the site should not have sundries such as stagnant water and pollution.
2) The steel strand should be cut with a disc grinding wheel cutting disc, and the arc cutting should not be used, and the incision should be smooth.
1) The two ends of the steel strand harness should be arranged in the same order, and each strand must be numbered and bundled, and the bunching method shall be specifically determined according to the form of the anchor used.
2) Steel strand loading and bunching.
a. The steel grain line loading site should be level, and it should not be pulled the concrete floor.
b. When the steel strand is loaded, the steel strand coil should be packed in the pay-off frame, and it should be gradually withdrawn from the coil.
c. The steel grain line is cut with a disc grinding wheel cutting machine, and arc cutting shall not be used.
d. The braiding of the steel strand should first straighten out the steel grain line, and then tie it with 20 iron wires, with a spacing of 1m, and try to make the steel strand tight.
e. After the prestressed tendon is completed, the spiral tube should be inspected, and if there is any damage, it should be repaired.
f. In case of narrow construction space, the bundle machine can be used to wear the bundle, and each must be numbered separately. The beam number is shown in the figure below, the threaded pipe number is beam number + English letters (such as yl1-a, yl1-b), and the steel strand number is beam number + English letters + Arabic numerals (such as yl1-a1, yl1-b12).
3) Bunching of steel strands.
The prestressed tendons of this project adopt the first piercing method, and the bundle is pierced by the bunching machine. The oil pump drives the chain plate to clamp the steel strand and transmit, the speed can be adjusted arbitrarily, and the beam can be advanced or retreated.
5.3. Exhaust hole (and water leakage hole) is set
1) make a hole in the spiral pipe, and then tie the plastic arc gland plate with a mouth with a steel wire with the pipe, and then insert it into the mouth with a 20 steel pipe, lead it out of the top surface of the component, and should be higher than the top surface of the concrete not less than 300mm between the gland plate and the spiral tube between the sponge gasket, and the periphery of the gland plate should be wrapped with sealing tape For curved holes, it is advisable to set up exhaust holes (and water leakage holes) at each wave peak.
2) Grouting hole setting;When the embedded hole is more than 30m, in addition to the existing grouting hole at the tensile end bell mouth, a grouting hole should also be arranged in the middle of the hole, and the spacing of the grouting hole should not exceed 30m, and the grouting hole should be set up in the trough for the curved hole. The method of setting the grouting hole is the same as that of the exhaust hole.
5.4. Prestressing equipment installation
1) When the tensioning equipment and implements are installed, the line of action of the tensile force should coincide with the center of the hole for the linear prestressed tendon: for the curved prestressed tendon, the line of action of the tensile force should coincide with the tangent line at the end of the center line of the hole, so that the three centers of the hole, the anchor ring and the jack are aligned.
2) The requirements for the installation of anchors should be as follows according to the different tensile anchorage systems of prestressed tendons
a. The anchorage system of the steel strand bundle clamp, when installing the anchor, attention should be paid to the centering of the working anchor ring and the anchor plate, the clamp is evenly tightened and exposed, and the hole position of the tool anchor on the jack and the hole position of the working anchor at the end of the component should be consistent, so as to prevent the steel grain line from crossing in the jack through the hole.
b. The clamp of the tool anchor should be kept clean and in a good lubrication state Before the new tool anchor clamp is used for the first time, the back of the clip should be coated with lubricant, and every 5-10 times after use, the baffle on the tool anchor should be removed together with the clip, and a layer of lubricant should be re-coated into the conical hole of the anchor plate.
On-site tensioning machine calibration and calibration
Before carrying out prestressed tensioning construction, the jack, oil gauge, fixture must be sent to the department with inspection qualification for inspection, calibration and correction, the prestressed tendon must be sent to the department with inspection qualification for inspection, and only after the technical performance and index of the tensile equipment, fixture and prestressed tendon meet the current national standards and design requirements are allowed to carry out prestressed tensile construction. During the construction process, the construction must also be carried out in accordance with the requirements of the "Construction Regulations for Prestressed Construction of Construction Projects" (CECS180-2005). Tensioning equipment and tools should be used together, before tensioning should be checked and calibrated for various tensioning equipment and instruments, and give the correct reading of the tensioning oil meter, according to the tension control stress, tensioning method and tensioning sequence provided by the design unit, take batch, phased symmetrical tensioning, but also should take into account to minimize the number of movements of tensioning equipment.
5.6 Tension Operation Procedure
This project adopts the method of tensioning at both ends, one end is tensioned first, the other end is tensioned, and the tension is supplemented and anchored. The tensile operation procedure is adopted: 0 10%-20%-50% 100 qcon anchorage (for low relaxation prestressed steel strand), or 0 initial tensile force n0 100 qcon load holding 2min qcon anchorage (for ordinary relaxation prestressed steel grain line).n0 is the starting point of measuring the elongation value, the value can be 10 20 qcon, the tension should be loaded in stages, and the elongation value should be measured at each stage of loading to determine the starting point of the elongation value and the actual elongation value.
5.7 sheets of pull calculation work
The design prestress control tensile stress is 1395MPa, and the ultimate strength of the steel strand is 1860MPa. The effective cross-sectional area of each strand is 140mm2, and the model number is 1524. The modulus of elasticity of the steel strand is 195×105 mpa。Tensioning at both ends is adopted, and the design tension of 14 bundles of each strand is 27342kn with an initial tensile force of 27342kn 。The theoretical elongation value and the range of elongation value are calculated by the following formula: δl = ppl ( a p ep) where: pp is the tensile force of the tendon (n);l is the calculated length of the tendon;ap is the cross-sectional area of the tendon (mm2);ep is the modulus of elasticity (n mm2) of the tendon. According to Article 7 of the "Prestressed Construction Regulations for Construction Projects" (CECS180-2005).2.Article 5 stipulates that when the stress control method is used for tensioning of the prestressed tendon, the tensile length value of the prestressed tendon should be checked. The deviation of the actual elongation value from the calculated elongation value should not exceed 6%. If the allowable deviation is exceeded, the cause should be identified and measures should be taken before continuing to stretch.
The elongation value of the prestressed steel strand in this project is shown in the following table
5.8 sheets of pull on-site control
The on-site tensioning must meet the "double control" standard, that is, when the control tension is met, the difference between the actual elongation value and the theoretical elongation value should be controlled within 6%, otherwise the tensioning should be stopped, the reasons for inspection and analysis should be checked, and the above requirements can be continued after taking measures to adjust, and the on-site tension measurement and recording should be done.
The application of 10% of the initial stress is to straighten the strand and overcome the downward deflection caused by the self-weight of the strand, the elongation value should be measured from the initial stress, and the actual elongation value should be added in addition to the measured elongation value. According to the requirements of the actual tensioning, it is necessary to make the "post-tensioned prestressed steel bar (wire) tension record" and record it in a timely and accurate manner, and the quality inspector should stand by the whole process and record the data. **Please refer to the attached file for details.
5.9. Cement slurry production and grouting
Cement slurry production
1) After the post-tensioning method has bonded prestressed tendons, the hole grouting should be carried out as soon as possible, the cement slurry in the hole should be full and dense, the grouting generally uses plain cement slurry, and the strength of the prepared cement slurry should not be less than 40MPa.
2) The water-cement ratio should generally be 04-045. When an appropriate amount of superplasticizer is added, the water-cement ratio can be reduced to o3s；Water and superplasticizer must have no corrosive effect on the prestressed tendons.
3) Through the experiment, the cement slurry can be mixed with appropriate expansion agent.
4) The fluidity of cement slurry should be controlled above 200mm.
5) The duration of the cement slurry from modulation to pouring into the pores, depending on the temperature situation, generally should not exceed 30 45min The stirred cement slurry must pass through the filter and be placed in the slurry storage barrel, and should be stirred frequently before use and during the injection process to prevent water precipitation.
Hole grouting
1) Before grouting, first of all, the machine preparation and test run should be carried out. The orifice should be rinsed clean and moistened.
2) The grouting sequence should be poured into the lower pores first, and then the upper pores should be poured, and the grouting should be carried out slowly and evenly, not interrupted, and should be vented smoothly.
3) The grouting pressure can be taken as 04～1.0n/mm2。When the orifice is longer or the slurry pipe is longer, the pressure should be larger, and vice versa, it can be smaller.
4) When the grouting is carried out until the exhaust hole comes out with thick slurry, the exhaust hole here can be blocked, and then continue to pressurize to 05-07n mm2, keep it for 1-2min and then close the grouting hole.
5) when grouting, for the more concentrated and adjacent holes, it is advisable to complete continuous grouting as much as possible, so as not to solidify the cement slurry that strings to the adjacent holes, and the blocked holes are not continuously grouted, and the holes of the post-grouting should be washed with pressure water before grouting unobstructed.
6) After grouting should be from the exhaust hole spot check grouting compactness, if there is any untruth, should be dealt with in a timely manner When grouting, each working shift should be left with no less than a group of side length of 70The 7mm cube specimen was cured for 28 days as standard, and its compressive strength was tested as the basis for evaluating the quality of cement slurry.
7) The hole grouting should be filled in the "prestressed hole grouting record form" to make a record, and the quality inspector should stand by the whole process and record the data. **See attachment for details.
5.10. Anchor end sealing
1) After the tensile tension is completed and passed the inspection, the excess tendon of the exposed anchor head can be cut, and the length of the retained tendon should not be less than 1 of the diameter of the prestressed tendon5 times, and should not be less than 30mm. After the grouting of the hole is completed, the anchor should be protected or the anchor concrete should be poured in time, and the anchor concrete should be strengthened.
2) The closed protection of the anchor should meet the design requirements;When there are no specific requirements for the design, the following provisions shall be met:
3) Effective measures should be taken to prevent anchor corrosion and mechanical damage.
4) The thickness of the protective layer of the protruding anchorage end anchor should not be less than 50mm.
5) The thickness of the protective layer of the exposed prestressed tendon should not be less than 20mm in a normal environmentWhen in a corrosion-prone environment, it should not be less than 50mm.
6.1 Master project
1) When the prestressed tendons enter the site, the specimens should be extracted for mechanical property testing in accordance with the current national standard "Steel Strands for Prestressed Concrete" GB T 5224, and their quality must meet the provisions of the relevant standards.
2) Anchors, clamps and connectors for prestressed tendons should be adopted according to the design requirements, and their performance should conform to the provisions of the current national standard "Prestressed tendon anchors, fixtures and connectors" GB T14370 and so on.
3) The cement for channel grouting should be made of ordinary Portland cement, and its quality should meet the provisions of the current national standard "Portland cement, ordinary Portland cement" GBL75, etc. The quality and application technology of admixtures for channel grouting should comply with the current national standards "concrete admixtures" GB8076, "Technical Regulations for the Application of Concrete Admixtures" GB50119 and other relevant environmental protection regulations.
6.2. Production and installation
1) When the prestressed tendon is installed, its variety, grade, specification and quantity must meet the design requirements.
2) During the construction process, the prestressed tendon should be avoided from being damaged by electric sparks, and the damaged prestressed tendon should be replaced.
6.3 sheets of pull
1) The tensile tensile and concrete strength of the prestressed tendon should meet the design requirements and should not be lower than 90 of the standard value of the design compressive strength of the concrete.
2) The tensile force, tensioning sequence and tensioning process of the prestressed tendon should meet the requirements of the design and construction technical scheme, and should meet the following requirements:
a.When the construction requires over-tensioning, the maximum tensile stress should not be greatly affected by the provisions of the current national standard "Code for Design of Concrete Structures" GB 50010.
b.When tensioning, the stress of each prestressed tendon in the same bundle should be uniform.
c.In the post-tensioning construction, when the prestressed tendons are bundle-by-bundle tensioning, it should be ensured that there is no unfavorable stress state to the structure at each stage, and at the same time, it is advisable to consider the influence of the elastic compression of the structural components generated by the post-batch tensile tendons on the prestressed tendons of the first batch to determine the tensile force.
d.When the stress control method is used to tension, the elongation value of the prestressed tendon should be checked, and the relative allowable deviation between the actual elongation value and the theoretical elongation value of the design calculation is 6.
e.In the process of tensioning, the prestressed tendon should be avoided to break or slip, when the fracture or slippage occurs, the number of fracture or slippage is strictly forbidden to exceed 3 of the total number of prestressed tendons of the same section, and each bundle of steel wire shall not exceed 1.
3) The prestressed construction should be reported to the third-party testing unit for testing, and the length of the reinforcing tendon should not be less than 1 when the prestressed tendon is detected5m。
6.4. Quality problems that should be paid attention to
1) In order to prevent the spiral pipe from being damaged and leaking, after the completion of the spiral pipe laying and fixing and the completion of the prestressed tendon bunching, the spiral pipe should be inspected.
2) In order to ensure that the position of the spiral pipe meets the design requirements, the sagittal height of the spiral pipe and whether the positioning reinforcement are firm should be checked. When pouring concrete, it should be forbidden for the vibrating rod to directly contact the spiral pipe.
3) In order to prevent concrete vibration leakage or holes in the bell mouth area, the vibration should be compacted when pouring concrete.
4) In order to prevent the leakage of the hole and plugging the hole when pouring concrete, in the process of concrete pouring, it is advisable to use a through-hole device to carry out the through-hole method regularly.
5) In order to ensure that the position of the bell mouth meets the design requirements, the bell mouth should be inspected before pouring concrete, and if it is found that its position is not fixed firmly with the formwork or non-prestressed steel bar, it should be corrected in time.
6) In order to prevent the exhaust hole from being blocked, the upper orifice of the plastic pipe of the exhaust hole should be sealed with tape before pouring concrete, so as to prevent the mortar from falling into the concrete when pouring concrete, and at the same time to prevent the plastic pipe from being flattened.
7) In order to prevent the prestressed tendons from being scratched or broken, the anchor clamp and the steel strand, the hole diameter of the limit plate and the diameter of the anchor hole, and the limit size of the limit plate should be checked before tensioningWhether the anchor is concentric with the flare;Whether the jack installation meets the "three hearts and one line".
8) In order to prevent the deviation of tensile length value from exceeding the standard, the reading of the oil pressure gauge should be accurate during tensioning, and the measured elastic modulus of the prestressed tendon should be used to calculate the theoretical elongation value.
9) When the steel strand is loaded and bundled, leave an appropriate steel strand processing area in the steel bar processing site, level the ground, and mark the line according to the length of the material on the site. The steel strand is cut and cut with a grinding wheel and then arranged into a bundle, tied with a wire every 1m, stacked according to the number classification, and listed to mark the length and design number, according to the number classification and stacking, the steel strand harness should be stacked to prevent bending and rainproof measures.
10) Tensioning method: the tension of the steel strand is mainly controlled by the stress control of the oil pressure gauge, and the tensile length value is measured for verification, and the error of the actual elongation value should be controlled within 6%, otherwise the cause must be identified and measures must be taken to adjust before the tensioning can be continued. When controlling tension, double-check the tension of each bundle.
11) Prestressed tension: before construction, jacks, high-pressure oil pumps with precision oil gauge 15-level 60MPa pressure gauge, calibrate the jack and pressure gauge with a pressure sensor with an accuracy of 1%. Before tensioning, carefully check whether the anchor lower backing plate, anchor ring, clip, limit plate, jack position, and formula anchor are on the center line.
6.5. Quality assurance measures in winter:
The project is expected to complete the prestressed beam concrete pouring on October 20, 2014, about November 15, 2014 concrete strength grade can reach 90% of the design strength, when the atmospheric temperature is lower than minus 5 degrees, will not be able to carry out the tensioning work of the prestressed steel strand, the steel strand tensioning operation is postponed to the next year when the atmospheric temperature is suitable.
In order to ensure that the steel strand is not corroded in the long winter and ensure the construction quality of the prestressed concrete beam, the following measures should be taken:
1) The size of the end of the protruding beam of the steel strand should be lengthened, which should not be less than 1900mm.
2) The metal bellows, bell mouth, anchor, and end steel strand are wrapped and closed with plastic cloth as a whole to prevent moisture from entering the bellows during the concrete pouring process and before tensioning.
3) After the concrete pouring is completed, the outside of the formwork and the concrete surface should be covered with an insulation layer, and the insulation layer adopts a dry rock wool quilt and an electric blanket to heat and insulate the newly poured concrete, and its covering thickness is not less than 4cm, and the insulation material should not be directly covered on the wet concrete surface, and the surface of the newly poured concrete should be covered with a layer of plastic film.
4) When the atmospheric temperature is between -10 and 20, an electric heating fan should be set up every 8-10m under the prestressed beam for heating and insulation.
1) The prestressed tendons made of blanking processing should be classified and stacked neatly, and there should be waterproof and moisture-proof measures, and no other heavy objects should be stacked on it.
2) The spiral pipe should be protected, and heavy objects should not be stepped on and stacked on it, and it is strictly forbidden to move its position in the subsequent process to prevent welding burns and hard object punctures.
3) The prestressed tendons and their embedded parts that have been laid should be strictly forbidden to move or damage during the construction of other follow-up processes.
4) Prestressed tendons and anchors should be strictly forbidden to lap with the power supply to prevent them from being damaged by electricity.
5) The on-site welding construction should be much higher spiral pipes, prestressed tendons and anchors to prevent welding burns.
8.1. Safety operation requirements
1) Prestressed construction operators should have a job certificate to enter the construction site should wear safety helmets, wear thick-soled shoes, high-altitude work should have a firm scaffolding, safety net.
2) When using electricity, it is strictly forbidden to mix the ground wire and the live wire, and it should be clearly marked to avoid connecting it with the structural steel bar, causing electric shock accidents.
3) The on-site switch box should take rainproof and moisture-proof measures, and install grounding protection devices to prevent leakage and electric shock.
4) All equipment should be inspected before use, and the faulty parts should be replaced, and the performance should be kept intact.
5) The pay-off worker of the steel strand should wear gloves to operate, and should not grab the end of the steel strand and pull the steel strand to prevent the steel strand from popping out and injuring people.
6) When cutting the prestressed tendons, the grinding wheel should be rotated before cutting, and no one should stand in the direction of the grinding wheel breaking and flying out during cutting.
7) When the oil volume of the oil pump tank is insufficient, it is necessary to refuel under no pressure, and it is strictly forbidden to replace it with alcohol, glycerin and water.
8) The hydraulic equipment should be equipped with a safety valve, and the maximum safety load should be preset before tensioningA safety valve is set between the jack and the high-pressure liquid hose to prevent the jack from suddenly returning to the top when the hose is broken.
9) When tensioning, the operator and other personnel are not allowed to stand behind the jack, only allowed to stand on both sides, in case of injury when the tendon is broken.
10) When measuring the elongation value, it is strictly forbidden to touch the cylinder block with your hands.
11) The calibrated supporting equipment is not allowed to be replaced. Although the operator should concentrate on the oil supply and return oil should be stable (including hypertension) should not exceed 80 of the standard value of tensile strength of prestressed tendons.
8.2. Environmental protection measures
1) Measures should be taken to control the construction noise generated when the prestressed tendons are cut and cut to minimize the noise disturbance to the people.
2) When the hole is grouted, attention should be paid to avoid the spraying of cement slurry to pollute the site;After the grouting is completed, the grouting equipment and site should be cleaned and cleaned in time, and the remaining cement slurry should be treated centrally and cannot be discharged at will.
8.3. Security measures
1) Implement the guidelines, policies and regulations on production and labor protection. Carry out safety education for employees, firmly establish the idea of "safety first", and adhere to the policy of "safe production and prevention first".
2) Establish and improve the safety production guarantee system, establish and implement the safety production responsibility system. The project manager is the first person in charge of safety, the deputy project manager in charge of construction and production is directly responsible for safety production, and the deputy manager of the project is responsible for labor protection and safety production. The managerial department has a leading group for safety production, a full-time safety inspection engineer, a full-time safety officer in the work area, and a part-time safety officer in the work class.
3) According to the actual situation of the group and the project, prepare detailed safety operation procedures, detailed rules, and formulate practical safety technical measures, distribute them to the work class, organize the learning and implementation of the Xi one by one, and do a good job in the "five simultaneities of safety" (that is: planning, arranging, inspecting, summarizing, and evaluating production at the same time, planning, arranging, inspecting, summarizing, and evaluating safety work) and "safety education".
4) Strictly implement the delivery system, and adhere to the "three-work system" activities of stressing safety before work, inspecting safety during work, and evaluating safety after work. Stick to a safe activity day every Monday.
5) Adhere to the special type of work with certificates.
6) Adhere to the regular safety inspection system. The project department inspects once a week, and the work class inspects once a day, and if unsafe factors are found, they immediately designate a special person to rectify them within a time limit.
7) Strengthen safety education, improve employees' safety awareness, establish the idea of safety first, and cultivate the necessary operational skills for safe production. Do a good job in the regular education of employees and the safety education of new workers, workers who change jobs, and special workers, and new workers are not allowed to work without education.
8) For the safety problems and potential safety hazards found in the inspection, a registration, rectification and elimination system should be established. Measures, funds, and completion dates must be taken before the hidden dangers are eliminated. If there is a danger to personal safety, stop the construction immediately, and the construction can only be carried out after the treatment is qualified.
IV. Annexes. 9.1. Post-tensioned prestressed steel bar (wire) tension record.
9.2. Grouting record table of prestressed holes.