中文摘要：

对于连续体系的钢-普通混凝土组合梁,处于负弯矩区的混凝土桥面板由于抗拉强度低,极易受拉开裂,导致组合梁的强度与耐久性下降.针对这一问题,提出了采用超高强度、高耐久性、高韧性且体积稳定性良好的活性粉末混凝土（RPC）材料代替普通组合梁中的混凝土桥面板,并根据RPC材料的本构关系及抗拉强度高的特点,确定以临界开裂状态作为这种新型钢,RPC组合梁的正截面破坏模式,推导了极限承载力计算公式,并对组合截面中RPC板与钢梁的高度比、宽度比、RPC板中的配筋率进行了参数影响分析.结果表明：钢-RPC组合梁与同条件的普通组合梁相比,在保证负弯矩区桥面板不开裂的情况下,极限承载力仍有所提高,并且结构的抗裂性、刚度和耐久性都可得到极大改善.

英文摘要：

Concrete slab in the negative moment area of continuous steel-concrete composite beams is prone to crack due to the low tension strength of common concrete,which could result in the decreasing of the strength and durability.To solve this problem,a method of replacing the concrete slab with reactive powder concrete（RPC） slab which is of super high strength,durability,toughness and volume stabilization is presented.According to the constitutive relation and the high tension strength of RPC,the normal section failure mode is defined as the critical crack state,and the calculation formula of ultimate bearing capacity is deduced.Finally,some parameters that influence the ultimate bearing capacity are analyzed,such as the height ratio of RPC slab to whole beam,width ratio of RPC slab to steel beam,and the ratio of reinforcement of RPC slab.Compared with the steel-concrete composite beams,it is indicated that in the precondition of RPC slab unallowable crack in negative moment area,the ultimate bearing capacity of steel-RPC composite beams can still be increased,and the crack resistance,stiffness and durability can all be enhanced greatly.