Improving the cracking resistance of steel-normal concrete (NC) composite beams in the negative moment region is one of the main tasks in designing continuous composite beam (CCB) bridges due to the low tensile strength of the NC deck at pier supports. This study proposed an innovative structural configuration for the negative bending moment region in a steel-concrete CCB bridge with the aid of ultrahigh performance concrete (UHPC) layer. In order to investigate the feasibility and effectiveness of this new UHPC jointed structure in the negative bending moment region, field load testing was conducted on a newly built full-scale bridge. The newly designed structural configuration was described in detail regarding the structural characteristics (cracking resistance, economy, durability, and constructability). In the field investigation, strains on the surface of the concrete bridge deck, rebar, and steel beam in the negative bending moment region, as well as mid-span deflection, were measured under different load cases. Also, a finite element model for the four-span superstructure of the full-scale bridge was established and validated by the field test results. The simulated results in terms of strains and mid-span deflection showed moderate consistency with the test results. This field test and the finite element model results demonstrated that the new configuration with the UHPC layer provided an effective alternative for the negative bending moment region of the composite beam.

由于 NC 桥面在桥墩支座处的抗拉强度较低，因此在负弯矩区域提高钢-正向混凝土 (NC) 组合梁的抗裂性是设计连续组合梁 (CCB) 桥梁的主要任务之一。本研究提出了一种借助超高性能混凝土 (UHPC) 层的钢-混凝土 CCB 桥梁负弯矩区域的创新结构配置。为了研究这种新型UHPC节点结构在负弯矩区域的可行性和有效性，对一座新建的全尺寸桥梁进行了现场载荷试验。新设计的结构配置详细描述了结构特性（抗裂性、经济性、耐久性和可施工性）。在实地考察中，在不同荷载工况下，测量了混凝土桥面、钢筋和钢梁在负弯矩区域的表面应变以及跨中挠度。此外，还建立了全尺寸桥梁四跨上部结构的有限元模型，并通过现场试验结果进行了验证。应变和跨中挠度的模拟结果与试验结果具有中等一致性。该现场测试和有限元模型结果表明，具有 UHPC 层的新配置为复合梁的负弯矩区域提供了有效的替代方案。建立了全尺寸桥梁四跨上部结构的有限元模型，并通过现场试验结果进行了验证。应变和跨中挠度的模拟结果与试验结果具有中等一致性。该现场测试和有限元模型结果表明，具有 UHPC 层的新配置为复合梁的负弯矩区域提供了有效的替代方案。建立了全尺寸桥梁四跨上部结构的有限元模型，并通过现场试验结果进行了验证。应变和跨中挠度的模拟结果与试验结果具有中等一致性。该现场测试和有限元模型结果表明，具有 UHPC 层的新配置为复合梁的负弯矩区域提供了有效的替代方案。