STEEL AND CONCRETE COMPOSITE ... ¢â‚¬¢ Composite Structures of steel and concrete: Beams, Slabs, Columns,

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  • Composite Structures Of Steel and Concrete 钢-混凝土组合结构

    By Professor. Shiming Chen 2015

  • • Part 1 What are composite structures • Part 2 References & assessment • Part 3 Introduction to composite

    structures Basic structural components: composite beams composite slabs composite columns

  • • What are composite structures(组合结构)? The structures consist of members of combining structural steel and concrete effectively.(型钢与混凝土的组合) ‘Composite construction’ Structural systems in which there is interaction between concrete and structural steel (钢与混凝土的共同作用)

    • Why is composite construction?

  • Example 1

  • Composite beam

    Non composite beam

  • Construction elements

    composite column floor = beam + slab composite beam

    composite slab

    6

  • Construction elements

    Composite slabs

    Reinforced concrete slab

    in-situ concrete on shuttering partially prefabricated slabs fully prefabricated slabs

    7

  • Construction elements

    Slabs Profile steel sheeting

    Interlock between steel and concrete

    frictional mechanical

    end anchorage8

  • • Composite construction is a product of recent design and construction practice, began just prior to the start of the twentieth century(20世 纪初).

    • Many countries have their own stories to tell about composite construction.

    • The first composite construction with design approval appeared in the year of 1894 when a bridge and a building were constructed in the USA, namely, the Rock Rapids Bridge in Rock Rapids, Iowa, and the Methodist Building in Pittsburgh.

  • • Many novel advantages: combining concrete and steel in the design of the primary structure for a high-rise building.

    • Using the best properties of both materials to solve the design challenge can result in a cost- effective solution that best meets a project’s architectural and functional requirements.

  • Strictly composite : • interaction of two materials within one

    construction element (e.g. a concrete-filled tubular steel column)

    • the philosophy of mixed building technology includes the combination of construction elements or members built up with different construction methods (e.g. concrete column in combination with a composite beam and a prefabricated slab).

  • Introduction to Composite Construction

  • some applications.

    Latitude at World square -Sydney

  • Latitude at World square -Sydney

  • Shanghai Tower in construction

  • Brief Introduction to Shanghai Tower • Location: Lujiazui Finance and Trade Zone, Pudong

    district, Shanghai, China • Owner/Developer: Shanghai Tower Construction and

    Development Co., Ltd. • Design Architect: Gensler • Local Design Institute: The Architectural Design &

    Research Institute of Tongji University • Structural Engineers: Thornton Tomasetti • Mechanical, Electrical and Plumbing (MEP) Engineers:

    Cosentini Associates • Date of Commence: Sep.18, 2010 • Date of Anticipated Completion: Dec. 30, 2014

  • 上海中心大厦结构体系特点

    • 地上124层, 高632m, 采用巨型框架-核心筒-伸 臂桁架抗侧力结构体系, 钢-混组合结构。 • 巨型框架结构由8根巨型柱、4根角柱以及8道 位于设备层箱形空间环带桁架组成

    • 核心筒为钢筋混凝土结构, 截面平面形式根据 建筑功能布局由低区的方形逐渐过渡到高区的 十字形;1~ 2区核心筒翼墙和腹墙中设置钢板, 形成了钢板组合剪力墙结构, 墙体中含钢率为 115% ~ 410%

  • Composite floor

  • • Aims of the course  To gain knowledge of composite structures

     To master design principle of composite structures

     To know key research/application topics in composite structures

     To develop comprehensive understanding of steel and concrete composite construction via summarizing and reporting on the selected topics

  • Reference books • Composite Structures of steel and concrete:

    Beams, Slabs, Columns, Frames for Buildings by R.P. Johnson Blackwell Publishing, 2004

    • Composite Construction, by D. Nethercot, Pron Press, 2004

    • Steel and Concrete Composite Structures, Lecture Notes by Shiming Chen, 2010

    • 钢-混凝土组合结构, by 陈世鸣,中国建筑工 业出版社,2013年

  • Chapter 1 Composite Construction- General

    • OBJECTIVE/SCOPE To introduce steel-concrete composite

    members and construction; to explain the composite action of the two different materials and to show how the structural members are used, particularly in building construction.

  • • 1.1 Why is composite construction • Traditional Structures for buildings: • Masonry structures • Wood structures • Steel structures • Steel reinforced concrete structures • Steel-concrete composite structures

    (composite structures as brief) • Other composite materials (FRP)

  • Comparison with other methods

  • Alternative Steel Beam Types

  • In a composite floor system the concrete acts together with the steel to create a stiffer, lighter, less expensive structure (Allen 1999)

    Metal Decking

  • Steel deck-concrete: composite construction

    • Composite decking works together with the concrete fill to make a stiff, light-weight, economical floor system

    • Composite decking is available in various profiles and thicknesses

  • Featues: Shear connector installation

    • The additional subcontractor needed for shear connector installation will increase field costs

    • Installation of shear connectors is another operation to be included in the schedule

    • A concrete flatwork contractor who has experience with elevated composite slabs should be secured for the job

  • Basic forms of composite construction

  • Conventional and innovative

    composite beams

    Composite beams

  • 1.2 Composite action in beams • Consisting of a steel section acting compositely

    with concrete slab. The two materials are interconnected by means of mechanical shear connectors.

    • A simply supported beams: under vertical loads, sagging bending moments cause tensile force in the steel section and compression in the concrete deck, optimum use of each material. At the steel/ concrete interface, mechanical shear connectors are provided to resist the horizontal shear.

  • If slip is free to occur, each component will act independently. If slip is eliminated, the slab and the steel member will act together as a composite unit.

  • Definitions for strength and stiffness properties • Complete and partial shear connection is regard

    to the design bending strength of the beam other than the horizontal shear resistance

    • Complete or incomplete interaction results in a more or less stiff composite beam

    • Composite beams are designed using plastic design methods and partial interaction theory, combing steel and concrete to great effect

  • • Shear connectors are commonly referred to as “studs” or “shear studs” in the trade

    • They are available in a range of sizes, materials, and grades

    • Headed studs (as shown) are most commonly used

    Shear Connectors

    Types of shear connectors

  • Shear connections

  • • Depending on the welding process used, the tip of the shear connector may be placed in a ceramic ferrule (arc shield) during welding to retain the weld

    • Shear connectors create a strong bond between the steel beam and the concrete floor slab which is poured on top of the metal decking

    • This bond allows the concrete slab to work with the steel beams to reduce live load deflection

    Shear Connectors

  • Composite beams, subject mainly to bending, consist of a steel section acting compositely with one (or two) flanges of reinforced concrete

  • 1.3 Composite floors or slabs • Composite floor: steel deck with additional

    indentations or embossments acts as both permanent formwork during concreting and tension reinforcement after the concrete has hardened.

  • • Main advantages to the designer and client • speed and simplicity of construction • lighter construction than a traditional concrete • less on-site construction

    high tolerances /under controlled factory conditions/ quality procedures.

    Rquired composite action can be achieved if: a. Mechanical interlock be provided by

    deformations in the steel profile b. Frictional interlock for profiles shaped c. End anchorage

  • Metal decking ready to be laid by hand

    Edge trims for metal deck floor construction

  • Floors using metal decking which is embossed to provide composite action.

    Composite slab

  • • As an alternative to wel

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