钢筋及混凝土强度等级对部分预应力梁静力抗弯性能影响的试验研究

摘要

For the bridge expansion project,chosen of reinforced concrete reasonable,both to ensure the requirement of bearing capacity designs,and can save economy effectively.Based on the 16 meters standard span prestressed concrete beam (C40,HPB300) in Beijing Hong Kong and Macao expressway (Beijing-Shijiazhuang section) reconstruction project.In this word,the reinforcement (HRB400) and concrete (C50) which frequently-used by project was chosen as the research object.The results show that the bearing capacity of reinforcing bar and concrete is increased by 12.25％ and the effect is the most obvious.The cracking load of beams is improved by strengthening concrete,and strengthening concrete affects stiffness of the beam before cracking,increases the bearing capacity of the beam.The bearing capacity of the beam is increased by reinforcing steel,and reinforcing steel improves stiffness of the beam in the experiment later,Increasing the grade of steel or concrete has no obvious effect on the ductility of the test beam.%对桥梁改扩建工程,合理选择钢筋混凝土既可以保证承载力的设计要求,又能有效节约成本.本研究以京港澳高速公路(京石段)改扩建工程中的16 m标准跨径预应力混凝土梁(C40,HPB300)为工程背景,分别选用工程中较常使用的钢筋(HRB300,HRB400)、混凝土(C40,C50)为变量对4根部分预应力混凝土梁进行抗弯试验.研究结果表明,同时提高钢筋与混凝土等级承载力提高12.25％,效果最明显;提高混凝土等级有利于提高试验梁的开裂荷载,影响梁开裂前的刚度,对承载力提高有一定辅助作用;提高普通钢筋等级可有效提高试验梁的承载力,以及试验后期梁的刚度;提高钢筋或混凝土等级对试验梁的延性影响不明显.