Experimental Study On Mechanical Properties Of Segmental Precast Assembled Concrete T-section Beams

At present,the country is actively promoting the development strategy of green assembled buildings,and assembled bridges will be an important direction for the future development of bridge engineering in China.In the thesis,the mechanical properties of segmental precast assembled concrete T-section beams are investigated by using indoor tests and finite element analysis,and the main research works are as follows:(1)With reference to the research results of domestic and foreign scholars and relevant codes and industry standards in recent years,we designed the length,section form,section size,section length,shear key type,number of key-joint,etc.of segmental precast assembled concrete T-section beams and fabricated four test beams;based on the research content of the mechanical properties of segmental precast assembled concrete T-section beams,we designed the test program.considering the cross-sectional characteristics of T-section beams,in order to prevent loading overturning,we designed the reinforced concrete T-section beams anti-tilt loading piers.(2)Carry out static load tests on segmental precast concrete T-section beams,observe and record the damage characteristics of the test beams during loading,including the location and corresponding load of the first crack,the time,location and distribution of subsequent cracks,etc.;analyze and obtain the strain variation law of internal reinforcement and concrete surface on both sides of the joint and in the span during loading,and the deflection variation law of span location.(3)Using the finite element software Abaqus,the plastic damage model of the four test beams was established,and the whole process from loading to damage of the four test beams was simulated,and the load-strain curves of the concrete surface and internal longitudinal reinforcement on both sides of the joint and in the span,and the load-deflection curves in the span were plotted using Origin software.The data obtained from both static load tests and numerical simulations were compared and analyzed to derive the effect of the studied parameters on the mechanical properties of segmental precast assembled concrete T-section beams.It is shown that increasing the number of key-joint(from single to double)improves the load carrying capacity of the test beam within a certain range.Under the same conditions,the deflection of the monolithic beam was the smallest,followed by the double,combined and single key-joint segmental T-section beams in that order.The strain on the concrete surface of the beam at both sides of the B-joint was the largest for the single-key-joint segmental T-section beam,followed by the combination key-joint,double-key-joint segmental T-section beam,and integral T-section beam in that order;while the strain at the span location was the largest for the integral T-section beam,followed by the single-key-joint,combination key-joint,and double-key-joint segmental T-section beam in that order.The internal longitudinal reinforcement strains at both sides of the joint and at the mid-span position,and the single key-joint segmental precast assembled concrete T-section beam is the largest,followed by combined key-joint and double key-joint segmental precast assembled concrete T-section beam in order.