建筑构造基础51885.ppt

1、第二章 基础 Unit Foundation,The foundation is located underground and forms the base of the building. The purpose of the foundation is to carry the load of the structure and spread it over a greater area, evenly and without undue settlement, to the ground beneath. The size and type of foundation depends

2、on the nature of the ground and the load carried by it.,第二章 基础,第一节 地基与基础的基本概念 地基：支撑建筑物的土层 一、天然地基和人工地基 Natural Ground and Artificial Ground （一）天然地基 Natural Ground： 天然的能够受力的土层。 种类,岩石 rock 碎石土 crushed stone soil 砂土 sandy soil 粘性土 clay 人工填土 earth-fill,（二）人工地基 Artificial Ground When the capacity of the s

3、oil to support loads isnt enough, artificial ground has to be used. 压实法 compaction method 换土法 replacement method 桩基 pile foundation compactor:压实机,replacement method To improve the bearing capacity in varying ground conditions, soft spots are usually filled with consolidated hardcore or a weak concre

4、te, before the foundation is laid. Consolidate: 加强、巩固 Hardcore:碎砖石 weak concrete：低标号混凝土,pile foundation When a foundation is laid in poor soil, it is necessary to excavate to a greater depth than normal to reach a solid base. If a good base cannot be found at a reasonable depth, then a so-called dee

5、p foundation must be provided. This usually comprises a series of driven or cast-in-situ reinforced concrete piles. Excavate: 开凿、挖掘,二、基础的埋置深度 The Depth of a Foundation,1、浅基础 shallow foundation 500MM埋置深度4米， 2、深基础 deep foundation 埋置深度4米,适宜的深度？ Which elements decide the depth of a foundation? 地基情况 the

6、nature of the ground 地下水位的影响 groundwater level 冰冻线 frost line 其它 other elements?,三、基础的类型 Types of the Foundations,（一）按基础的形式分类dividing foundations by forms 1、条形基础 Strip Foundation 特点：连续的带形，也可叫带形基础。 适用情况：当地基条件好，基础埋置深度较浅时。,材料：砖、石、混凝土、钢筋混凝土,适用什么样的上部结构？,2、独立式基础 Individual Footing 特点： 呈独立的块状，形式有杯形、阶梯形、锥形。

7、 Socket foundation 杯形基础 Benched foundation 阶梯形基础 Cone foundation 锥形基础,A socket foundation is the footing with socket for a prefabricated column.,适用情况：当上部结构为框架时。 frame structure:框架结构 材料：钢筋混凝土。,3、联合基础Combined Footing 1）柱下条形基础 Strip Foundation under Columns：将柱下独立基础连接起来，形成连续的条形基础。,Isolated columns are n

8、ormally supported on square concrete foundation bases. Where such columns are spaced at close intervals, it is often more practical to provide a continuous concrete strip foundation to carry a complete row, as is done for load bearing walls.,2）柱下十字交叉基础 Crossed Strip Foundation under Columns： 将条形基础做成

9、网格状，提高了基础的稳定性，使荷载分布更为均匀。,3）梁板式基础 Beam and Slab Foundation： 有肋筏板基础。,4）板式基础 Mat Foundation： 筏板基础 Raft Where the bearing capacity is particularly poor or the quality of the soil varies considerably, a raft foundation is often recommended to support normal buildings. This type of foundation simply consi

10、sts of a reinforced concrete slab, on which the walls are built.,5）箱形基础 Box Foundation(Cellular Mat) 钢筋混凝土板与地下室墙组合的结构。 basement: 地下室 basement wall: 地下室墙,6）桩基Pile Foundation：桩、桩帽和系梁的系统，将建筑物荷载向下传递到适当的持力层。 bearing stratum: 持力层 pile cap: 桩帽、桩台 tie beam: 系梁,机械成孔灌注桩、人工挖孔桩、混凝土预制桩、管桩、高压旋喷桩、摆喷桩,钻孔桩,搅拌桩等,（二）按

11、材料分类：刚性基础、柔性基础 dividing foundations by materials 1、刚性基础 Rigid Foundation： 材料：砖、石、混凝土 抗压但抗剪和抗弯能力差。 compressive resistance: 抗压 shearing resistance:抗剪 bending resistance :抗弯 刚性角：rigid angle 拉力: tensile force 压力: pressure 剪力: shear,2、柔性基础 Flexible Foundation： 抗压和抗弯剪能力都很好，不受刚性角的限制。 材料：钢筋混凝土,第二节 常用刚性基础构造P

12、art The Construction of Common Rigid Foundation,一、砖基础 Brick Foundation 1、强度 strength：砖的强度不得低于MU10 垫层 bed course： 水泥砂浆 三七灰土 三合土,二、石基础 Stone Foundation 毛石基础 Rubble Foundation 尺寸：宽度和厚度150MM，长度为宽度的 52。5倍。 强度：M5 CONSTRUCION：,料石基础 Squared Stone Foundation： 经过加工后的石料。 基础的宽度除了按计算要求外，还应符合料石的规格尺寸。,三、混凝土及毛石混凝土基础Concrete and Rubble Concrete Foundation,满足刚性角的要求 什么情况下用毛石混凝土基础呢？ 当混凝土基础体积过大时，可以填充一些毛石。,第三节 基础沉降缝构造Part The construction of Foundation Set