اتصالات ومحكم كردن سازه (متن به زبان انگليسي مي باشد

[امید عباسی]

Introduction

This presentation was developed as a teaching aid with the support of the American Institute of Steel Construction. Its objective is to provide technical background and information for connections and bracing configurations. The information provided is based on common design and construction practices for structures of twelve stories or less.

The AISC Digital Library case study presentations document the construction of a steel frame for an office building. The case study includes photographs that were taken throughout the construction of the structural steel frame including detailing, fabrication, and erection. Project data including plans, schedules, specifications and other details are also included. The case study presentations are available in the Learning Opportunities section at www.aisc.org.

This presentation goes a step further in detail in the areas of connections and bracing configurations. A more in-depth background is provided and details of common connections and bracing configurations are presented.

The information is presented with concerns of a construction manager or general contractor in mind.

[امید عباسی]

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General knowledge of structural steel

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Knowledge of the types of steel frame connections defined in the American Institute of Steel Construction design specification

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An understanding of different types of connections used in structural steel frames

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Insight into the impacts of using certain connection types

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Familiarity with common bracing systems used in structural steel frames

[امید عباسی]

Some benefits associated with use of structural steel for owners are:

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Steel allows for reduced frame construction time and the ability to construct in all seasons

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Steel makes large spans and bay sizes possible, providing more flexibility for owners

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Steel is easier to modify and reinforce if architectural changes are made to a facility over its life

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Steel is lightweight and can reduce foundation costs

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Steel is durable, long-lasting and recyclable (AISC 1999)

[امید عباسی]

Procurement and management of structural steel is similar to other materials, but there are some unique aspects to steel construction:

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Steel is fabricated off-site (above left)

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On-site erection is a rapid process (above right)

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This gives use of structural steel some scheduling advantages

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Coordination of all parties is essential for achieving potential advantages

(AISC 1999)

[امید عباسی]

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Forces from gravity, wind, and seismic events are imposed on all structures

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Forces that act vertically are gravity loads

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Forces that act horizontally, such as stability, wind and seismic events (the focus of this discussion) require lateral load resisting systems to be built into structures

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As lateral loads are applied to a structure, horizontal diaphragms (floors and roofs) transfer the load to the lateral load resisting system

(AISC 2002)

Structural Steel Frame Elevation

[امید عباسی]

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The type of lateral load resisting system to be used in a structure should be considered early in the planning stage

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Lateral stability as well as architectural needs must be met

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The three common lateral load resisting systems are:



1.Braced Frames


2.Rigid Frames


3.Shear Walls