It is essential to reliably predict the human-induced vibrations in serviceability design of footbridges to ensure the vibration levels to be within the acceptable comfort limits. The human-induced structural responses are dependent on the dynamic properties of structures and human-induced excitations. For concrete footbridges, the elastic modulus of concrete is a vital parameter for determining the dynamic structural properties. To this end, a two-stage machine learning (ML)-based method is first proposed for modeling the elastic modulus of concrete. At the first stage, the ensemble algorithm, i.e. the gradient boosting regression tree (GBRT), is used to predict the compressive strength by selecting eight parameters, including concrete ingredients and curing time, as the inputs. At the second stage, the elastic modulus of concrete is modeled by using the GBRT method with the compressive strength as the input. Pedestrian crowd-induced load is the most common and crucial design load for footbridges. To consider the inter- and intra-subject variability in walking parameters and induced forces among persons in a crowd, a load model is developed by associating a modified social force model with a walking force model. By integrating the two submodels of structure and excitation, an intelligent analysis method for human-induced vibration is finally developed. A concrete footbridge with typical box cross-section subjected to human-induced excitation is analysed to illustrate the application of the proposed method.

中文翻译：

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混凝土人行桥人振智能分析方法

在人行天桥的可维护性设计中可靠地预测人为振动以确保振动水平在可接受的舒适范围内至关重要。人为结构响应取决于结构的动态特性和人为激发。对于混凝土人行天桥，混凝土的弹性模量是决定结构动力特性的重要参数。为此，首先提出了一种基于两阶段机器学习 (ML) 的方法来模拟混凝土的弹性模量。在第一阶段，使用集成算法，即梯度提升回归树（GBRT），通过选择混凝土成分和养护时间等八个参数作为输入来预测抗压强度。在第二阶段，以抗压强度为输入，采用GBRT方法对混凝土的弹性模量进行建模。行人引起的荷载是人行天桥最常见和最关键的设计荷载。为了考虑人群中步行参数和诱导力的主体间和主体间变异性，通过将改进的社会力模型与步行力模型相关联来开发负载模型。通过整合结构和激励两个子模型，最终开发出一种人致振动的智能分析方法。分析了具有典型箱形截面的混凝土人行桥受到人为激励，以说明该方法的应用。行人引起的荷载是人行天桥最常见和最关键的设计荷载。为了考虑人群中步行参数和诱导力的主体间和主体间变异性，通过将改进的社会力模型与步行力模型相关联来开发负载模型。通过整合结构和激励两个子模型，最终开发出一种人致振动的智能分析方法。分析了具有典型箱形截面的混凝土人行桥受到人为激励，以说明该方法的应用。行人引起的荷载是人行天桥最常见和最关键的设计荷载。为了考虑人群中步行参数和诱导力的主体间和主体间变异性，通过将改进的社会力模型与步行力模型相关联来开发负载模型。通过整合结构和激励两个子模型，最终开发出一种人致振动的智能分析方法。分析了具有典型箱形截面的混凝土人行桥受到人为激励，以说明该方法的应用。通过整合结构和激励两个子模型，最终开发出一种人致振动的智能分析方法。分析了具有典型箱形截面的混凝土人行桥受到人为激励，以说明该方法的应用。通过整合结构和激励两个子模型，最终开发出一种人致振动的智能分析方法。分析了具有典型箱形截面的混凝土人行桥受到人为激励，以说明该方法的应用。