山东理工大学：《荷载与结构设计方法》课程教学课件（讲稿，双语）Chapter 2 Gravity Load

Chapter 2 Gravity Load 2.1 Structure self-weight 2.2 Floor and roof live load 2.3 Snow load 2.4 Crane load 2.5 Vehicle load 2.6 Assembly of person load 2.7 Soil vertical earth pressure and lateral pressure G 归东理子大军 SHANDONG UNIVERSITY OF TECHNOLOGY

Chapter 2 Gravity Load 2.1 Structure self-weight 2.2 Floor and roof live load 2.3 Snow load 2.4 Crane load 2.5 Vehicle load 2.6 Assembly of person load 2.7 Soil vertical earth pressure and lateral pressure

2.1 Structure self-weight Cause:gravity由地球引力引起 Assumption:uniformly distributed in calculation Calculation:the total self-weight of structure members can be expressed as 台 G-total self-weight of structure members Yi-bulk unit weight of i-th member Vi-volume of i-th member 归东理王大军 SHANDONG UNIVERSITY OF TECHNOLOGY

2.1 Structure self-weight • Cause: gravity 由地球引力引起 • Assumption: uniformly distributed in calculation • Calculation: the total self-weight of structure members can be expressed as 𝐺𝐺 = � 𝑖𝑖=1 𝑛𝑛 𝛾𝛾𝑖𝑖𝑉𝑉𝑖𝑖 𝐺𝐺 -total self-weight of structure members 𝛾𝛾𝑖𝑖-bulk unit weight of i-th member 𝑉𝑉𝑖𝑖-volume of i-th member

2.1 Structure self-weight Simplified Calculation:structure is viewed as a whole Typical bulk unit weight of structures Wood structure 2.0~2.5 k N/m3 Steel structure 2.5~4.0 k N/m3 RC structure 5.0~7.5 k N/m3 归东理工大军 SHANDONG UNIVERSITY OF TECHNOLOGY

2.1 Structure self-weight • Simplified Calculation: structure is viewed as a whole • Typical bulk unit weight of structures ▫ Wood structure 2.0~2.5 𝑘𝑘 𝑁𝑁⁄𝑚𝑚3 ▫ Steel structure 2.5~4.0 𝑘𝑘 𝑁𝑁⁄𝑚𝑚3 ▫ RC structure 5.0~7.5 𝑘𝑘 𝑁𝑁⁄𝑚𝑚3

2.2 Live load on floor and roof 1. Live load on floor of residential building民用建筑楼面活荷载 Definition:gravity actions due to assembly of persons,furniture and facilities.The magnitude varies with time and the location is movable. Therefore,this live load is also called variable load. Depending on variation characteristic with time,live load can be divided into: 。 Sustained live load持久性活荷载 在某个时间段内基本保持不变的荷载，如家具、物品、常住人员等。 Intermittent live load临时性活荷载 楼面上偶尔出现的短期荷载，如聚会人群、装修材料的堆积等。 :大军 SHANDONG UNIVERSITY OF TECHNOLOGY

2.2 Live load on floor and roof 1. Live load on floor of residential building民用建筑楼面活荷载 ▫ Definition: gravity actions due to assembly of persons, furniture and facilities. The magnitude varies with time and the location is movable. Therefore, this live load is also called variable load. Depending on variation characteristic with time, live load can be divided into: • Sustained live load 持久性活荷载 在某个时间段内基本保持不变的荷载，如家具、物品、常住人员等。 • Intermittent live load 临时性活荷载 楼面上偶尔出现的短期荷载，如聚会人群、装修材料的堆积等

2.2 Live load on floor and roof 1.Live load on floor of residential building民用建筑楼面活荷载 Determination: The determination of nominal value,combination value,frequent value and quasi-permanent value can refer to Table 5.1.1 in Code (Table2-1 in textbook) 表5.1.1民用建筑楼面均布活荷载标准值及 其组合值、频遇值和准永久值系数 项次 类别 标准值组合值疑语值 准永久值 kN/㎡燕数中，系数中 系数中。 (1】住宅、宿舍、能馆、办公楼、 2.0 0.7 0.5 0.4 医腕病房、托儿所、幼儿园 (2引试验室、阅览室、会议室、医 2.0 0.7 0.6 05 院门诊童 教室、食堂、餐厅、一般资料档 2.5 0.7 0.6 0.5 案室 归东理工大军 SHANDONG UNIVERSITY OF TECHNOLOGY

2.2 Live load on floor and roof 1. Live load on floor of residential building民用建筑楼面活荷载 ▫ Determination:  The determination of nominal value, combination value, frequent value and quasi-permanent value can refer to Table 5.1.1 in Code (Table2-1 in textbook)

2.2 Live load on floor and roof 1.Live load on floor of residential building民用建筑楼面活荷载 Reduction on nominal value: When the room is large,the uniformly distributed load is less possible to be imposed on all the area of room with the magnitude of nominal value. Therefore,the variation of actual load distribution should be considered in design of beam,wall,column and foundation.Accordingly,reduction should be conducted on nominal values. 归东理子大军 SHANDONG UNIVERSITY OF TECHNOLOGY

2.2 Live load on floor and roof 1. Live load on floor of residential building民用建筑楼面活荷载 ▫ Reduction on nominal value:  When the room is large, the uniformly distributed load is less possible to be imposed on all the area of room with the magnitude of nominal value. Therefore, the variation of actual load distribution should be considered in design of beam, wall, column and foundation. Accordingly, reduction should be conducted on nominal values

2.2 Live load on floor and roof 1.Live load on floor of residential building民用建筑楼面活荷载 Reduction on nominal value: The most widely used reduction methods are semi-empirical. ·International practice国际通行做法 ·Calculation of live load on beam计算梁的楼面活荷载效应 Forresidential building and offices:+8 For public facility and therooms:=0.58m where A is tributary area of beam梁的从属面积 的东理王大军 SHANDONG UNIVERSITY OF TECHNOLOGY

2.2 Live load on floor and roof 1. Live load on floor of residential building民用建筑楼面活荷载 ▫ Reduction on nominal value:  The most widely used reduction methods are semi-empirical.  International practice 国际通行做法  Calculation of live load on beam 计算梁的楼面活荷载效应 For residential building and offices: 𝜆𝜆 = 0.3 + 3 𝐴𝐴 , 𝐴𝐴 > 18𝑚𝑚2 For public facility and the rooms: 𝜆𝜆 = 0.5 + 3 𝐴𝐴 , 𝐴𝐴 > 18𝑚𝑚2 where A is tributary area of beam 梁的从属面积

2.2 Live load on floor and roof 1.Live load on floor of residential building民用建筑楼面活荷载 Reduction on nominal value: The most widely used reduction methods are semi-empirical. ·International practice国际通行做法 ·Calculation of live load on column,wall or foundation of multi-story building计算多层房 屋的柱、墙或基础的楼面活荷载效应 For residential buildingfce:+ For public facility and the rooms:m where n is number of stories above calculating cross-section所计算截 面以上楼层数 归东罪子大军 SHANDONG UNIVERSITY OF TECHNOLOGY

2.2 Live load on floor and roof 1. Live load on floor of residential building民用建筑楼面活荷载 ▫ Reduction on nominal value:  The most widely used reduction methods are semi-empirical.  International practice 国际通行做法  Calculation of live load on column, wall or foundation of multi-story building 计算多层房 屋的柱、墙或基础的楼面活荷载效应 For residential building and offices: 𝜆𝜆 = 0.3 + 0.6 𝑛𝑛 , 𝐴𝐴 > 18𝑚𝑚2 For public facility and the rooms: 𝜆𝜆 = 0.5 + 0.6 𝑛𝑛 , 𝐴𝐴 > 18𝑚𝑚2 where n is number of stories above calculating cross-section 所计算截 面以上楼层数

2.2 Live load on floor and roof 1.Live load on floor of residential building民用建筑楼面活荷载 Reduction on nominal value: The most widely used reduction methods are semi-empirical. ·Code《建筑结构荷载规范》GB50009-2012 1设计楼面梁时： 1)第1(1)项当楼面梁从属面积超过25m2时，应 取0.9； 2)第1(2)~7项当楼面梁从属面积超过50m2时，应 取0.9； 3)第8项对单向板楼盖的次梁和槽形板的纵肋应取0.8， 对单向板楼盖的主梁应取0.6，对双向板楼盖的梁应 取0.8； 4)第9~13项应采用与所属房屋类别相同的折减系数。 的东理王大军 SHANDONG UNIVERSITY OF TECHNOLOGY

2.2 Live load on floor and roof 1. Live load on floor of residential building民用建筑楼面活荷载 ▫ Reduction on nominal value:  The most widely used reduction methods are semi-empirical.  Code 《建筑结构荷载规范》GB50009-2012

2.2 Live load on floor and roof 1.Live load on floor of residential building民用建筑楼面活荷载 Reduction on nominal value: The most widely used reduction methods are semi-empirical. ·Code《建筑结构荷载规范》GB50009-2012 2设计墙、柱和基础时： 1)第1(1)项应按表5.1.2规定采用； 2)第1(2)~7项应采用与其楼面梁相同的折减系数； 3)第8项的客车，对单向板楼盖应取0.5，对双向板楼 盖和无梁楼盖应取0.8； 4)第9~13项应采用与所属房屋类别相同的折减系数。 注：楼面梁的从属面积应按梁两侧各延伸二分之一梁间距的范围内的 归东理子大军 实际面积确定。 SHANDONG UNIVERSITY OF TECHNOLOGY

2.2 Live load on floor and roof 1. Live load on floor of residential building民用建筑楼面活荷载 ▫ Reduction on nominal value:  The most widely used reduction methods are semi-empirical.  Code 《建筑结构荷载规范》GB50009-2012