【作者】 王革；

【导师】 何建；

【作者基本信息】 哈尔滨工程大学 ， 土木工程， 2015， 硕士

【摘要】 本文以大跨度楼盖为研究对象,首先分析了在人行荷载作用下普通实心四边简支楼盖的振动响应问题,以结构动力学为理论基础,采用理论计算和数值模拟两种方法对该问题进行了分析。利用有限元软件模拟了四边固支预应力大跨度楼盖在人行荷载工况下的振动响应,并对其舒适度进行评价。本文的主要内容如下:1、介绍了步行荷载的形式,分析了影响人群荷载作用的各项人致参数,本文采用傅里叶级数形式表达的单步落足函数,根据本文所研究的问题对函数进行了简化,略去高阶量的影响,只取第一阶谐波,同时在进行人群行走工况分析时,考虑保守情况,即所有行人以同频同步的行走方式作用在楼盖上。2、由于大跨度楼盖的厚度远小于平面尺寸,因此本文以薄板振动理论为理论基础。现有的楼盖设计规范中,人行荷载被当做静荷载施加在楼盖上,与实际情况差距较大,而且理论分析中一般不考虑行人对楼盖的影响。本文将二维人行桥人致振动问题中的驱动力概念引入三维的楼盖振动分析中,考虑到行人体系阻尼给楼盖带来的影响,得到了楼盖的动力平衡方程,对已有的单人行走情况的连续化落足公式,以及人群作用下的固定多人行走公式进行了一定的修改,得到了楼盖的振动响应表达式。3、利用ABAQUS有限元软件,模拟了15m×15m的大跨度楼盖算例。在模拟单人行走时,考虑最不利加载方式,在楼盖中心施加一阶的傅里叶级数形式的人行荷载;在模拟人群荷载作用时,采用了60人固定加载方式,所施加的荷载与单人行走工况相同,得到了楼盖的振动特性及振动响应,包括各阶固有频率及相应的振动模态,楼盖的竖向位移和加速度的时程曲线。通过与理论计算结果的对比,发现理论计算结果与模拟结果较为接近,验证了本文所提出的人—楼盖耦合模型的正确性。4、模拟了预应力大跨度楼盖在两种荷载工况下的振动响应,参照舒适度衡量标准,选取楼盖的加速度作为评价指标。在所选取的6个测点处,最大加速度值均没有超过美国AISC-Ⅱ所规定的最大值0.05 m/s~2,满足舒适度的要求。更多还原

【Abstract】 Focused on a long-span floor t,this paper first analyzes the vibration response of the solid floor with four simply supported edges under pedestrian load.Based on the structural dynamic theory,theoretical calculation and numerical simulation for the problems are used.Using the finite element software to simulate the prestressed long-span floor with four edges clamped the paper analyzes the vibration response under the pedestrian load condition,and evaluate its comfort,which contributes to the contents as follows:1.The paper introduces the form of the pedestrian load,and analyses the parameter which affects the throng pedestrian load.The function of the single step expressed by fourier series are adopted,and is simplified because of the problems of the paper.The higher-order parts are ignored and the first harmonic is left.All people walk on the floor with the same frequency and phase when analyzing the condition throng pedestrian load.2.Because the thickness of the long-span floor is much less than its length and width,the theory of vibration plate is the basic theory.Existing code of floor designing treating the pedestrian load as a kind of static load,but it is entirely different from the actual conditions.What is more,the influence brought by the people is out of the analyzing.The paper brings the concept of tractive force into the analyzing for floor.A new equation is got considering the influence of the people’s damp.The paper modifies the existing formula on the vibration response under the single and throng pedestrian load,.3.An example of a long-span floor with the size of 15 m ×15m is simulated with the finite elements software ABAQUS.A first-order single pedestrian load is exerted to the centre of the floor which is the most negative condition when considering the single person;60 loads is exerted at the fixed points when considering the throng pedestrian condition.The results of the response includ inherent frequency,mode,concentration-time curve of acceleration,concentration-time curve of displacement.By comparing the result of the calculation and simulation,the paper verifies the correctness of the coupling model between the people and floor proposed by the paper.4.The paper simulates the response of the prestressed long-span floor.According to the standard of comfort,the acceleration is adopted to be the index to evaluate the comfort.The result shows that the prestressed floor meet the demands of comforts.更多还原