Abstract:High-strength lightweight concrete (HSLWC) with strength grade above CL40 is applied to long-span bridge structure, which has the advantages of reducing dead weight, effectively reducing structural internal force, increasing span and reducing the number of piers. A 3-span prestressed high-strength lightweight aggregate concrete continuous rigid frame bridge was designed according to 1/4 ratio based on Dalianba section No. 14 of Anning to Chuxiong Expressway in Yunnan province. The bridge deck structure was made of CL50 concrete, and a variety of load conditions were tested. The results show that the prestressed high-strength lightweight aggregate concrete continuous rigid frame bridge has good mechanical performance, and all the indexes meet the standard requirements when 1 times and 1.5 times equivalent vehicle load passes through. When the double equivalent vehicle load passes, some indexes do not meet the requirements of use, but the bridge shows good ductility. In the case of severe overload, although the damage of the bridge is serious, it can still maintain a good bearing capacity level and will not collapse.

Abstract:The reinforcement technology of prestressed aramid fiber cloth with permanent anchorage is developed, the construction technology of concrete flexural members reinforced by prestressed aramid fiber cloth with permanent anchorage is given, the stress relaxation loss test research of prestressed aramid fiber cloth is carried out, the bending, shear and fatigue performance test research of prestressed aramid fiber cloth reinforced concrete beam is carried out, and the temperature bonding of aramid fiber cloth is carried out Experimental study on the influence of mechanical properties of materials. The test results show that the cracking load, yield load, ultimate load, fatigue life and flexural stiffness of the prestressed aramid fiber reinforced concrete beam with permanent anchorage are significantly increased compared with the unreinforced reference beam. When the ambient temperature is below 60℃, the bonding strength of the matching resin adhesive and the base adhesive of the aramid fiber cloth will not soften. The experimental research and analysis show that the reinforcement technology of prestressed arylon fiber cloth with permanent anchorage can significantly improve the mechanical properties of concrete flexural members in the use stage.

Abstract:The corrosion protection of rock and soil prestressed anchor cable is very important, once stress corrosion occurs, it may cause fatal damage. Many projects in our country pay more attention to the application of anchoring force, but lack of understanding of corrosion damage and anti-corrosion of anchoring cables. This paper discusses the corrosion mechanism and characteristics of rock-soil prestressed anchor cables, compares the difference of anti-corrosion requirements of rock-soil anchorage codes at home and abroad, and puts forward some anti-corrosion suggestions for rock-soil prestressed anchor cables which are suitable for the characteristics of anchorage engineering in China.

Abstract:Tunnel anchors are ideal for large suspension Bridges in mountainous areas because of their high cost performance and low environmental disturbance. The prestressed pipe of the tunnel anchor is generally equipped with a bending beam steering part. For an unbonded replaceable anchor filled with grease in the pipe, a steering device composed of a splitter pipe is provided in the bending beam steering part. Compared with the straight pipe, the existence of the steering device makes it more difficult to thread, fill and seal the pipe. In this paper, an experimental study on the simulated construction of prestressed anchor with bent beam is carried out for Aizhai extra-large suspension bridge in Hunan province. The feasibility of the beam threading process is tested through the beam threading test, and the test shows that the beam threading is smooth and the steel strand will not be twisted during the beam threading process. The feasibility of cable changing process is verified by cable changing test, which shows that single cable changing can be realized smoothly. The feasibility and sealing effect of the oil filling process were tested by the oil filling sealing test, which showed that the hole could be filled smoothly and the system had no leakage. The experience accumulated through the simulation test provides reference for the practical project and the similar projects in the future.

Abstract:In the study of the static uniaxial test of the new composite anchorage structure, three groups of comparative tests were carried out, that is, different specific area, different material strength and different weakening hole depth were considered. The test results show that: (1) In the three groups of single factor comparison test, the three groups of specimens with larger area, higher material strength and deeper weakening hole have more obvious weakening effect; (2) The thickness of anchoring zone is the fourth factor affecting weakening effect; (3) The specific area, weakening hole depth and anchoring zone thickness all have the best values, which can make the weakening effect optimal; (4) The mechanism of the weakening effect is that under the condition that the thickness of the anchoring zone is sufficient, the weakening zone generally goes through various stages of deformation - large deformation - fracturing - crushing - compaction, and at the same time absorbs a large amount of explosion energy, so that the crisis of the anchoring zone (including the surface of the cavity) can be transferred, and therefore has huge economic and technical effects. The experimental research provides the necessary basis for the optimization design of the weakening effect of the new composite anchorage structure.

Abstract:(Continuation of the previous period) ② The column with the extension arm (7, 6, 5 and 5 ', 6 ', 7 ') is installed with two pairs of hoists at the same time, and the lifting arm is turned in the center after the volleys. Move the lift forward to the installation node, and then slowly loosen the auxiliary lifting point to make the member turn over and vertical, and then install in place, as shown in Figure 26a), b), c).