Integral bridges are preferred on infrastructure schemes as they have lower maintenance costs than a conventional jointed bridge. A key aspect of integral bridge design is the assessment of long-term passive resistance that develops in the abutment backfill due to seasonal movements of the superstructure. This resistance is currently defined by an intermediate earth pressure coefficient termed K*, and is typically evaluated using the limit equilibrium (LE) approach prescribed in BSI PD-6694-1:2011+A1:2020. This paper adopts the alternative numerical design approach and investigates the development of K* behind full-height abutments using soil–structure interaction (SSI) modelling in Plaxis-2D software. The study demonstrates that mobilised passive resistance is primarily a function of backfill and structural stiffnesses, and that the current LE approach does not capture the backfill resistance profile correctly. The effectiveness of the SSI method was verified by comparison to the LE method. The current study provides an SSI methodology that is an efficient design approach, and which is suitable for a wide variety of integral bridge arrangements beyond the current LE method applicability.

中文翻译：

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整体桥台背后的土-结构相互作用

整体桥梁在基础设施方案中是首选，因为它们的维护成本低于传统的连接桥梁。整体桥梁设计的一个关键方面是评估由于上部结构的季节性运动而在桥台回填中形成的长期被动阻力。该阻力目前由称为K *的中间土压力系数定义，通常使用 BSI PD-6694-1:2011+A1:2020 中规定的极限平衡 (LE) 方法进行评估。本文采用替代数值设计方法并研究了K的发展* 在 Plaxis-2D 软件中使用土壤-结构相互作用 (SSI) 建模的全高桥台后面。该研究表明，动员的被动阻力主要是回填和结构刚度的函数，并且当前的 LE 方法不能正确捕捉回填阻力曲线。通过与 LE 方法的比较验证了 SSI 方法的有效性。目前的研究提供了一种 SSI 方法，这是一种有效的设计方法，适用于超出当前 LE 方法适用范围的各种整体桥梁布置。