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The goal is to develop an understanding for the building structure as a system that supports and as a pattern

that orders space and makes it possible. Structural computer modeling is introduced where the treatment of

structures is broadened and enriched by integrating the traditionally separate fields of: construction,

structural analysis, structural design, structural systems, materials, geometrical modeling, visual

communication and, presentation. The students have to synthesize the knowledge acquired in various

courses and have to set up a mathematical model of the building support structure, rather than solving a given

isolated analysis or design problem, as is usually done in education; they have to deal with the physical

reality of the entire building rather than only an isolated part.

The primary structural engineering software used in this context is SAP2000 V.11 developed by

COMPUTERS AND STRUCTURES (CSI), Berkeley, CA, USA (http://www.csiberkeley.com/); it is widely employed in practice and in numerous universities internationally. The program is fully integrated within

Microsoft Windows and allows modeling of nearly all types of structures. The Windows based easy-to-use

graphical interface permits the quick modeling of structures with templates and then to edit them via the

graphical interface. Free educational demo versions of the software are available from CSI. Since the demo

versions of the CSI software are limited to 100 nodes, generally only planar structures are investigated by the

students.

The program helps students to visualize the building as an assembly of linear elements (e.g. beams,

columns, arches, cables), planar elements (e.g. walls, slabs, shells, flexible membranes), or spatial elements

(e.g. solids). Students have to define: geometry, material, member types, member sections, static load cases

and load combinations. Then they set up the mathematical model for the building support structure by

assigning the member types and sections, the external support joints, possibly constraints, the frame end

releases (internal member joints), and the load types.

It is not necessary for the students to set up equations although assumptions and limitations of the method of

analysis will be discussed. But it must be emphasized that finite element computer programs do not only

represent a powerful method of engineering analysis, they also represent a tool for learning. The student

must understand the physical reality of the building structure in every detail to set up the model he puts into

the computer. He develops a feeling and control over the support structure by zooming from the global scale

of the overall building behavior to the local scale of stress and detail.

PROJECTS: they are an integral part of the workshop, see PROJECTS 2009

VISITING PROFESSOR WOLFGANG SCHUELLER

Department of Architecture Xian University of Architecture and Technology

A WORKSHOP ON BUILDING

SUPPORT STRUCTURES:

A visual study with computers

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BIBLIOGRAPHY

1. Building Support Structures, Analysis and Design with SAP2000 Software, with attached CD, published by Computers and Structures Inc., Berkeley, CA, 2009, 620 pages,

http://orders.csiberkeley.com/SearchResults.asp?Cat=2&Redirected=Y

2. The Design of Building Structures [] , 2 volumes, Prentice Hall W.Wolfgang Schueller[], www.china-pub.com .

3. Manuals of CSI programs on CD, especially, Getting Started-Basic Analysis Reference Tutorial Manuals, see also for further information,

http://www.comp-engineering.com/SAPManE.htm

4. Refer also to: Beijing Civil King Software Technology Co., Ltd., Beijing, Chushu LI, PHD, S.E., Chief

Executive, Tel:86-10-8838 3866-101, Mobile:13601318851, Fax:86-10-88381056,

Email: csli@chinabuilding.com.cn, Web: http://www.bjcks.com/ ,

web: http://www.csiberkeley.com

Qualified universities are eligible for free software for Education and Research. 5. Dr. Software's products: http://www.drsoftware-home.com/

6. West Point Bridge Designer, version 4.1.1, which was developed by Colonel Professor Steve Ressler at

the U.S. Military Academy, West Point, NY. (bridgecontest.usma.edu/index.htm).

TENTATIVE OUTLINE OF WORKSHOP

week 1

Introduction: Building Structures as Architecture

The necessity of structure: order, structure is a necessary part of life

The purpose of building structure: ordering system, form giver, support structure

Building vs. Structure vs. Architecture: structure is necessary for buildings but not for architecture: without structure no building, but architecture as an idea does not require structure

Position of structure: hidden exposed innovative standard construction

Building structure types vs. building use: single volume with large spans - cellular subdivision with multiple small spans - longs-span stadiums vs. massive building blocks vs. high-rise towers

Structure systems: horizontal-span vs. vertical-span structures, lowrise vs. high-rise building structures, two-dimensional vs. three-dimensional structures

Building shapes and forms: there is no limit to building shapes ranging from boxy to compound hybrid to organic and crystalline shapes. Traditional architecture shapes are based on the primary

geometrical solids the prism, pyramid, cylinder, cone, and sphere. The modernists invented an

almost inexhaustible number of new building shapes through transformation and arrangement of basic building shapes, through analogies with biology, the human body, crystallography, machines,

tinker toys, flow forms, and so on. Classical architecture, in contrast, lets the faade appear as a

decorative element with symbolic meaning.

Structure as support: strength - stiffness - stability: main bearing structure vs. secondary structure vs. exterior envelope gravity structure vs. lateral force resisting structure structure patterns dimensional coordination - cantilever tower vs. gravity structure from the bearing structure to the modern hybrid structure

Structural behavior: Loads: gravity vs. lateral loads (wind, seismic) external vs. internal forces, static loads vs. dynamic loads Force flow: flow along members - path to the ground where

foundations make the transition possible to the weak soil - stresses (intensity of force flow, blood

pressure) depends on: member shape, material, size, structure, connections; Force vs. form

Basic structural elements: beams, columns, frames, arches, surfaces, spatial shapes, free form

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Introduction to Projects

Discussion and selection of projects

Stage 1: geometrical order of building, spatial grid organization

Spatial awareness:

Definition of building shapes by contour lines - the geometry of interior volumes - geometrical layout of

building structure as defined by the horizontal planes (plans) and the vertical building planes (sections and

elevations), and as defined by the interaction of the planes which form the space (e.g. axons, relationship of

plan to section) - grids and line diagrams as organizers - dimensional coordination.

Introduction to Structural Computer Modeling

Modeling the structure/ mathematical models/ structural computer software/ finite elements/ typical computer

input/ typical computer output/ Mathematical models for structure systems - introduction to SAP2000

Nonlinear V11.

Introduction to Structure Systems: AXIAL SYSTEMS

Trusses are typical examples of axial structure systems. Because of their simplicity of behavior they provide an ideal introduction to computer analysis. Trusses are composed of frame elements, which are modeled as

straight lines connecting two joints, which are called nodes. It is assumed that the members in trusses are

pin-connected and subject only to joint loads, hence only axial internal member forces are generated.

For determinate structures disregard the effect of material and member sizes (i.e. use using either elements

with zero moments of inertia or using default setting), since member stiffness has no effect on the magnitude

of internal member forces, however do not use deflection results.

Trusses Introduction to planar truss systems

Problem 1, 2 : the generation of trusses: simple, basic truss forms are generated as based on the Howe-type

of member layout (a similar approach can be used for other common layouts such as Pratt, Warren, K-truss,

lattice). Then make the following changes by reshaping the truss configuration that is play with the truss

object by considering:

Profile: rectangular, triangular, curved, trapezoidal, and other asymmetrical shapes, i.e. contours

Load arrangement, load direction, and load location: symmetrical and asymmetrical, vertical and horizontal

Support location and orientation: simple beams, cantilever beams, overhanging beams, frames, etc.

Simple truss types: funicular trusses, fan trusses, compound trusses, complex trusses

Cable Structures Introduction to cable structures: cable-supported beams (sub-tensioned beams), cable-stayed bridges, cable-

stayed roof structures

Problem 3, only for demonstration of stayed bridges

week 2:

Discussion of Projects

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Project stage 2: brainstorming the idea of the building

Within the spatial network: structure layout

Introduction to Structure Systems: FLEXURAL SYSTEMS

The frame element is used to model axial truss members as well as beam-column behavior in planar and

three-dimensional skeletal structures. In contrast to truss structures, the joints may not be hinged but rigid.

The loads may not be applied at the nodes but along the members causing a member behavior much more

complicated than for trusses. Each frame element has its own local coordinate system for defining section

properties and loads, and for interpreting output data. By default all frame members are rigidly connected to

the nodes, therefore at pinned joints all the moments must be released. Release one or more of the

element degrees of freedom from the joint, when it is known that the corresponding element force or

moment is zero.

Beams and Floor Framing Review of beams and beam behavior under load action - beam types - multi-span beam systems: the effect of

load arrangement - the effect of span - the effect of support location and support type - load types and load

distribution - moment diagrams vs. suspended cable structures (i.e. active structures) - introduction to floor

framing Problem 3: various beam types are investigated with respect to: boundary

conditions, load types, load distribution, indeterminate action

Problem 4: steel beam design

Problem 5: concrete beam design

Problem 6: multi-span beam types are investigated with respect to: span,

continuity, live load arrangement, hinging

Problem 10: introduction to floor framing

Problem 11: floor framing 2

week 3:

Discussion of Projects

Project stage 3: gravity load analysis of building

Behavioral Awareness: The response of structure (i.e. axial force diagrams, shear and moment diagrams, member deflections), to

gravity force flow as seen in the horizontal and vertical building planes - the effect of geometrical layout of

structure on magnitude of force flow - the interplay of force and form (tectonics) - the effect of scale -

structural integrity and redundancy - the efficiency of form.

Beam as Surface Structure Introduction to finite surface elements: 3-dimensional shells, and planar membrane (e.g. walls) and plate

elements (e.g. slabs) - the effect of mesh geometries and arrangement - discussion of the stress contour plot

displaying the variation of stress of the model

Problem 13: simply supported beam modeled using membrane element analysis and regular shape elements Problem 14: deep beam behavior

Problem 15: simple square slab systems modeled with plate elements the effect of support types and location

week 4:

Discussion of Projects

Project stage 4: LATERAL load analysis of building

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Behavioral Awareness: The response of structure (i.e. axial force diagrams, shear and moment diagrams, member deflections), to

lateral forces of wind and seismic action as seen in the vertical planes - the effect of geometrical layout of

structure on magnitude of force flow - the interplay of force and form (tectonics) the lateral stability of the building - the effect of scale - structural integrity and redundancy - the efficiency of form.

Introduction to Structure Systems: FLEXURAL-AXIAL SYSTEMS

Any type of material can be defined and assigned to a frame element. You can run the analysis and get forces for that frame element (not stresses). If the material type is Steel or Concrete then you can design the

element using the built-in design post processors. For Wood you can put in member sections and get forces

but not stresses. You only get stresses for frame elements in a design post processor, which SAP2000 does

not have for wood.

Frames The geometry of frames rectangular frames vs. pitched frames vs. arches - funicular frames pressure line response to various load actions - the effect of the frame profile on uniform gravity load action - the behavior

of simple statically determinate frames (single-bay, multi-bay, single-story, multi-story) under gravity and

lateral force action - the braced frame - eccentric vs. concentric bracing - knee-braced portal frames - stability

and redundancy of simple frames

three-hinge arches/frames - the difference between folded beams and arches - lateral thrust under gravity

action

Problem 16: folded beam system

Problems 8, 9, 10: steel, wood, and concrete columns

Problem 17: three-hinged frame structure systems

Problem 18: introduction to indeterminate frames two-hinged portal frames the effect of indeterminacy Problem 19: The effect of member sizes on force flow in indeterminate frames Problem 20: basic arches

Introduction to Structure Systems:

FORM-RESISTANT STRUCTURE (rigid and flexible)

week 5

Discussion of Projects

Project stage 5: LATERAL STABILITY of building

Material Awareness: Member span vs. member size - density of member arrangement - scale of structure - interaction of structural

elements - interaction of structural and non-structural elements such as curtains and partitions - detail as

connection, linkage of structural elements - materiality - composition

Introduction to the Response of Buildings to Lateral Force Action

Roof/Floor Diaphragms Lateral stability of buildings - the response of buildings to lateral force action: (1) lateral force-resisting

structure systems, (2) diaphragm action of floor and roof structures, (3) lateral building deflection - the

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distribution of lateral forces to the vertical lateral force-resisting structures:(1) statically determinate

conditions, (2) statically determinate conditions due to symmetry, (3) torsion (closed shafts)

Lateral Stability of Buildings Problem 21: Investigate the simple single-story, 4.50-m high, braced, hinged frame structure by treating the

roof diaphragm as rigid and then as flexible. First the lateral-force resisting structure is arranged

symmetrically so that there is no torsion under symmetrical load action, but provide a lateral brace in the

short direction so that the building is stable, in general, and not just for the symmetrical condition. Then the

lateral-force resisting structure is arranged asymmetrically. Draw the 6-bay building on a 6.00 x 7.50 m grid.

Assume a uniform wind pressure of 1 kN/m2 against the short building faade. First model the floor/roof as

rigid diaphragm (e.g. concrete over metal deck) by assigning diaphragm constraints, then model the roof as

flexible diaphragm (e.g. roof deck with no concrete).

Problem 22: Concrete slab diaphragms with concrete shear walls

Final Presentation of Projects

Project stage 6: ARCITECTURE

The interaction of material, structure, detail (construction) and space - other meaningful relationships - the

building as an idea where geometry is used as organizer - the compositional basis of space and detail - the

expression of structure.

Grading system

Homework exercises (40%) + Project stages (30%) + Final Project (20%) + Course involvement including

attendance (10%)