CE 151- Chapter 1

60問 • 2年前

問題一覧

the prediction of the performance of a given structure under prescribed loads and/or other external effects, such as support movements and temperature changes

Structural Analysis

Performance Characteristics/ Design Considerations

Stresses, Deflections, Support Reactions

what are the 3 stresses or stress resultant

Axial Forces, Shear Forces, Bending Moments

engineers began applying the knowledge of mechanics in designing structures Mechanics → mathematics and science

Middle Of 17th Century

originator of the theory of structures

Galileo Galilei

developed the law of linear relationships between the force and deformation of materials.

Robert Hooke

formulated the laws of motion and developed calculus

Sir Isaac Newton

formulated the principle of virtual work

John Bernoulli

developed the theory of buckling of columns

Leonhard Euler

presented the analysis of bending of elastic beams

C. de Coulomb

published a treatise on elastic behavior of structures in 1826

L. M. Navier

formulated the three-moment equation for the analysis of continuous beams

B. P. Clapeyron

presented the method of consistent deformations and the law of reciprocal deflections

J. C. Maxwell

developed the conjugate-beam method for calculation of deflections and ________ circles of stress and strain

Otto Mohr

formulated the theorem of least work

Alberto Castigliano

developed the moment-area method

C. E. Greene

presented a principle for constructing influence lines

H. Muller-Breslau

developed the slope-deflection method slope-deflection method → precursor of the matrix stiffness method

G. A. Maney

developed the moment-distribution method in 1924

Hardy Cross

revolutionized structural analysis

Computers

the science and art of planning, designing, and constructing safe and economical structures that will serve their intended purposes

Structural Engineering

integral part of any structural engineering project

Structural Analysis

➢ prediction of the performance of the proposed structure

Structural Analysis

involves the establishment of the functional requirements of the proposed structure, the general layout and dimensions of the structure, consideration of the possible types of structures that may be feasible and the types of materials to be used

Planning Phase

perhaps the most crucial phase of the entire project and requires experience and knowledge of construction practices in addition to a thorough understanding of the behavior of structures

Planning Phase

sizes of the various members of the structural system selected in the planning phase are estimated based on approximate analysis, past experience, and code requirements

Preliminary Structural Design

involves determination of all loads that can be expected to act on the structure

Estimation Of Loads

values of the loads are used to carry out an analysis of the structure in order to determine the stresses or stress resultants in the members and the deflections at various points of the structure

Structural Analysis

results of the analysis are used to determine whether or not the structure satisfies the ________________ requirements of the design code

Safety And Serviceability Checks

if the code requirements are not satisfied, then the member sizes are revised, and phases 3 through 5 are repeated until all the safety and serviceability requirements are satisfied

Revised Structural Design

➢ subjected to pure tension under the action of external loads ➢ composed of flexible steel cables, vertical rods used as hangers, membrane structures such as tents ➢ support bridges and long-span roofs

Tension Structures

➢ develop mainly compressive stresses under the action of external loads ➢ columns and arches columns – straight members subjected to axially compressive loads beam – column → when subjected also to lateral loads and/or moments arch – a curved structure, with a shape similar to that of an inverted cable ➢ susceptible to buckling or instability → adequate bracing must be provided

Compression Structures

➢ composed of straight members connected at their ends by hinged connections to form a stable configuration ➢ loaded only at the joints ➢ members either elongate or shorten ➢ support roofs of buildings

Trusses

➢ used in multistory buildings to reduce lateral movements due to wind loads and earthquake excitations ➢ example is reinforced concrete shear walls

Shear Structures

➢ develop mainly bending stresses under the action of external loads ➢ commonly used are beams, rigid frames, slabs, and plates beam

Bending Structures

three-dimensional structures can be subdivided into plane structures for analysis

Plane Versus Plane Structure

all the members of a structure as well as the applied loads lie in a single plane

Plane Structure

representation of analytical model of a body selected for analysis

Line Diagram

used to join members of structures

Connections

prevents relative translations and rotations of the member ends connected to it

Rigid Connections

all member ends connected to a rigid joint have the same translation and rotation

Rigid Connections

prevents only relative translations of member ends connected to it

Hinged Connections

all member ends connected to a hinged joint have the same translation but may have different rotations

Hinged Connections

3 types of Supports

Fixed, Hinged, Roller

do not allow any movement

Fixed Supports

can prevent translation but permit rotation

Hinged Supports

can prevent translation in only one direction

Roller

actions of other bodies on the structure under consideration

External Forces

2 types of external Forces

Applied Forces, Reaction Forces

usually referred to as loads

Applied Forces

exerted by supports on the structure

Reaction Forces

forces and couples exerted on a member or portion of the structure by the rest of the structure

Internal Forces

used to attach structures to the ground or other bodies

Supports

restrict movements under the action of applied loads

Supports

a structure that maintains its shape and remains a rigid body when detached from the supports

Internally Stable

a structure that can’t maintain its shape and may undergo displacements under small disturbances when not supported externally

Internally Unstable

supported by exactly three reactions

Statically Determinate Externally

supported by more than three reactions

Statically Indeterminate Externally

If a structure is supported by fewer than three support reactions

Statically Unstable Externally

unstable due to improper arrangement of supports

Geometrically Unstable Externally

Xeth LE 5

Mharvie Nagal · 39問 · 2年前

Xeth LE 5