1001页：A013 消防建筑施工：建筑基本常识-中国救援装备网

建筑消防基本常识A13

图片内容

It goes from zero to insanity in 3 seconds.

从零到疯只要3秒~

We really need to discuss your driving attitude.

咱们得好好合计一下你这态度。

双语：

Definitions of Loads

荷载的定义

A load in a building works to destroy the gravity resistance system of the structure.

建筑的荷载和抗重力系统是一对生死冤家。

According to NFPA 5000: Building Construction and Safety Code, loads are “forces or other actions that result from the weight of all building materials, occupants and their possessions, environmental effects, differential movement, and restrained dimensional changes.”

根据《NFPA 5000：建筑施工和安全规范》的定义，所谓荷载就是所有建筑材料，内部人员和其财物的重量，环境的影响，差动和有限形变产生的力或其他作用。

Specific terms are used to describe the various types of loads and the way they are placed on a building.

不同类型的荷载有对应的术语，用以描述荷载如何对建筑产生影响的。

It is important to understand and use these terms correctly.

理解和正确使用这些术语非常重要。

Dictionary definitions are not always identical to the definitions used in the construction field.

字典里的解释并不一定和现实一致。

In addition, the various terms are not always mutually exclusive. For example, a load may be a live load and an impact load at the same time.

此外，术语之间也不是完全互斥。比如，荷载可以是动荷载，也可以是冲击荷载。

Stress and Strain

应力和形变

Before we proceed any further, we must first understand the concepts of stress and strain, the result of forces applied to a structural member.

在继续深入学习之前，我们先得搞清楚应力和形变的概念，这是将力施加在建筑结构上产生的结果。

In the common vernacular, stress and strain are considered synonyms; however, a clear understanding of the technical definitions of these terms is critical for fire fighters.

一般说来，应力和形变意思差不多。不过，把这些术语的专业解释搞清楚点对于消防员来说总没坏处。

As we have discussed, an external force that acts on a structure is called a load.

如前所述，作用在结构上的外力被称为负载。

The internal forces that resist the load are called stress and strain.

抵抗负载的内力就是应力和形变了。

Stress is the force per unit area that produces a deformation.

应力是单位面积上抵抗外力导致的变形的力。

It is usually measured in pounds per square inch (psi), although occasional references to pounds per square foot (psf) are also found.

常规度量单位是磅/平方英寸（psi），偶尔也会看到磅/平方英尺（psf）

The unit area measurement is at the discretion of the person making the calculations.

数字的单位是由计算这个数字的人自行选择的。

Always be careful to note the unit area when examining any calculations.

所以，在检视任何计算结果时务必注意单位。

KIP, a term meaning 1,000 pounds, is used in engineering calculations where the number would be so large as to be unwieldy.

KIP，1000磅（力），在充斥着大数字的工程计算中应用较多。

Strain, in contrast, is the actual percentage of elongation (deformation) that occurs when a material is stressed. It is measured in fractions of an inch of deformation per inch of original length of the material.

与此相反，形变是材料在在承受应力时的延伸率（变形）。体现的是每英寸材料伸长量和原长度的比值。

Compression, Tension, Torsion, and Shear Forces

压力，张力，扭力，剪力

Generally, four types of forces can be applied to a structural member: compression, tension, torsion, and shear Figure 2-2.

通常，建筑结构承受四种类型的力：压力、张力、扭力和剪力。图2-2

In essence, a compressive force is one in which the force squeezes a structural member, such as a concrete column supporting a floor.

本质上，压力是一种挤压结构构件的力，比如混凝土桥墩对桥面的支撑。

Tensile forces stretch a member such as a steel cable that is supporting a suspended walkway.

张力拉伸构件，例如支撑悬索桥的钢缆。

A torsional force is a twisting force such as that created by turning a screwdriver on a screw; it is the result of torque (the measurable turning force applied to a structural member).

扭力来自于扭转力，比如用螺丝刀拧螺丝；是扭矩（施加在构件上可测量的转动力）的产物。

Shear forces occur within a building member when opposing forces pull the member in opposite directions and are often the result of wind loads.

当建筑构件承受两个相反反向的力同时作用时，其内部就会出现剪力，通常由风压产生。