B.structures report-project2 done

SCHOOL OF ARCHITECTURE, BUILDING & DESIGN Centre for Modern Architecture Studies in Southeast Asia (MASSA) Bachelor of Science (Honours) (Architecture) BUILDING STRUCTURES [ARC 2522/ 2523]

Project 2 -‐ Extension of a R. C. bungalow

LING TECK ONG 0303127 CHUNG KA SENG 0316922 POH WEI KEAT 0303646 LEE YIANG SIANG 0302966

CELINE TAN JEAN INN 0303669 WONG SOON FOOK 0302953 WONG KIEN HOU 0312104 WONG JIA XIN 1101G13277

Tutor: Mr. Mohd Adib Ramli

Table of Content 1.0 Introduction of the case study

2.0 Measured Drawings

3.0 3D Model

3.1 Perspective views

3.2 Structural layout

4.0 Case study: Appraisal of structural system

4.1 Structural element

4.2 Structural system of case study

4.3 Indication on plans

4.4 Distribution in the structure

5.0 Conclusion

6.0 References

1.0 Introduction

In this project, we are introduced to structural theory, force calculation and basic

structural proposal. This project will allow us to understand the building structure. Our

case study is a two storey bungalow house. It is located at No. 4, Jalan SS1/ 34, Seksyen

26, Petaling Jaya, 46300 Sea Park, Selangor. This bungalow has quite a large garden area

at the side.

Observations of the structure of the bungalow were made and recorded. We are

able to identify the columns and beams from our site visit.

The bungalow has 5 bedrooms. An extension has been made to the bungalow.

The side is extended by 2 terraces on the ground floor while the back is extended by

adding a space for utility and wet kitchen.

Our case study is using column and beam structural system and the orthographic

drawing of the bungalow is provided in order to help our understanding of the building

structure.

Figure 1: Front facade of bungalow

Figure 2: Extended area -‐ 2 terraces

Figure 3: Extended area -‐ wet kitchen and utility room

Figure 4: Land area available for extension

Figure 5: Existing column located in the Figure 6: Existing column located in the

living room still in use after dry kitchen still in use after

extension extension

2.0 Measured Drawings

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3.0 3D Model 3.1 Perspective Views

Figure 7: front perspective view

Figure 8: right perspective view

Figure 9: left perspective view

Figure 10: right perspective view

Figure 11: bird eye view

3.2 Structural Layout

4.0 Case study: Appraisal of structural system 4.1 Structural element

The studied bungalow is identified to be using shallow foundation and pad footing is

used.

Figure 7: section of pad footing

-‐ most economical shallow foundation types but are more susceptible to differential

settlement.

-‐ usually support single concentrated loads, such as those imposed by columns.

-‐ isolated or independent slab of concrete foundation to support concrete columns or

steel pillars, detached brick or masonry piers.

-‐ the pier or column bearing on the centre point of the slab.

-‐ the thickness is govern by the same consideration as for strip footing and is made not

less than the projection of the slab beyond the face of the column or pier, or the edge

of the base plate of a steel stanchion.

-‐ in whatever circumstances the thickness should be less than 150mm thick, and should

the base become very "wide and thicker", the reduction in thickness can be effected by

introducing reinforcement to the slab.

Figure 8: pad footing showing grade beam

Shallow Foundations

Shallow foundation systems can be classified as spread footings, wall and continuous

(strip) footings, and mat (raft) foundations. Variations are combined footings,

cantilevered (strapped) footings, two-‐way strip (grid) footings, and discontinuous

(punched) mat foundations.

Grade beam

A grade beam or grade beam

footing is a component of a

building's foundation. It

consists of a reinforced

concrete beam that transmits

the load from a bearing wall

into spaced foundations such

as pile caps or caissons. It is

used in conditions where the

surface soil’s load-‐bearing

capacity is less than the

anticipated design loads.

Combined footings

(Fig. 8) are used

where the bearing

areas of closely

spaced columns

overlap.

Figure 8: combined footing

Figure 8: cantilever footing

Figure 9: continuous footings for (a) a wall, (b) several columns

Cantilever footings

(Fig. 9) are designed

to accommodate

eccentric loads.

Continuous wall

and strip

footings (Fig. 9)

can be designed

to redistribute

bearing-‐stress

concentrations

and associated

differential

settlements in

the event of

variable bearing

conditions or

localized

ground loss

beneath

footings.

Figure 10: reinforced concrete building elements

To distribute the load of the foundation on the soil, spread footings are installed below

the building's foundation. This type of footing is continous below the perimeter of the

house walls and may be thickened or widened at the points where concentrated loads

are applied e.g. columns. These components are constructed from concrete and are

often reinforced with rebar or steel to add additional support. Depending on the size

and configuration of the building, the footers can be buried just below ground level or

several feet below the surface. In cold climates, they are always placed below the frost

line to minimize problems with concrete heaving that occurs during freeze/thaw cycles.

This type of footer design is highly beneficial to builders and homeowners. Since they

transfer the weight of the building over a large area, they have little risk of failure.

Reinforced Concrete Column

A reinforced concrete column is a structural members designed to carry compressive

loads, composed of concrete with an embedded steel frame to provide reinforcement.

For design purposes, the columns are separated into two categories: short columns and

slender columns.

Short Column A short column is a structural member whose relatively short length virtually ensures it

will fail in compression if it is evenly loaded along its axis. Columns can be classified as

short, intermediate, or long, depending on their lengths, their material properties, and

the lengths of other columns in the same structure. A short column differs from a

medium or long column, each of which can fail by bending when evenly loaded along the

axis.

Slender Column A slender column is one whose length is large in comparison to its cross-‐sectional

dimensions and, when loaded to its extreme, fails by buckling (abruptly bending) out of

its straight-‐line shape and suddenly collapsing before reaching the compressive

strength of its material. This is called a condition of instability. An intermediate column

falls between the classifications of short and slender. When loaded to its extreme, the

intermediate column falls by a combination of compression and instability.

Reinforced Concrete Beam

A beam bends under bending moment, resulting in a small curvature. At the outer face

(tensile face) of the curvature the concrete experiences tensile stress, while at the inner

face (compressive face) it experiences compressive stress.

Singly Reinforced Beam A singly reinforced beam is one in which the concrete element is only reinforced near

the tensile face and the reinforcement, called tension steel, is designed to resist the

tension.

Doubly Reinforced Beam A doubly reinforced beam is one in which besides the tensile reinforcement the

concrete element is also reinforced near the compressive face to help the concrete resist

compression. The latter reinforcement is called compression steel. When the

compression zone of a concrete is inadequate to resist the compressive moment

(positive moment), extra reinforcement has to be provided if the architect limits the

dimensions of the section.

Under-‐Reinforced Beam An under-‐reinforced beam is one in which the tension capacity of the tensile

reinforcement is smaller than the combined compression capacity of the concrete and

the compression steel (under-‐reinforced at tensile face). When the reinforced concrete

element is subject to increasing bending moment, the tension steel yields while the

concrete does not reach its ultimate failure condition. As the tension steel yields and

stretches, an "under-‐reinforced" concrete also yields in a ductile manner, exhibiting a

large deformation and warning before its ultimate failure. In this case the yield stress of

the steel governs the design.

Over-‐Reinforced Beam An over-‐reinforced beam is one in which the tension capacity of the tension steel is

greater than the combined compression capacity of the concrete and the compression

steel (over-‐reinforced at tensile face). So the "over-‐reinforced concrete" beam fails by

crushing of the compressive-‐zone concrete and before the tension zone steel yields,

which does not provide any warning before failure as the failure is instantaneous.

Balanced-‐Reinforced Beam A balanced-‐reinforced beam is one in which both the compressive and tensile zones

reach yielding at the same imposed load on the beam, and the concrete will crush and

the tensile steel will yield at the same time. This design criterion is however as risky as

over-‐reinforced concrete, because failure is sudden as the concrete crushes at the same

time of the tensile steel yields, which gives a very little warning of distress in tension

failure.

4.2 Structural System of Case Study

Moment Resisting Frames

Moment-‐resisting frames are rectilinear assemblages of beams and columns, with the

beams rigidly connected to the columns. It is use to resist lateral forces by the

development of bending moment and shear force in the frame members and joints.

By virtue of the rigid beam-‐column connections, a moment frame cannot displace

laterally without bending the beams or columns depending on the geometry of the

connection.

Flexural yielding of beams and columns and shear yielding of column panel zones are

the primary source of lateral stiffness and strength for the entire frame. Beam column

joints in a reinforced concrete moment resisting frame are crucial zones for transfer of

loads effectively between the connecting in the structure.

Types of joints in frames

The joint defined as the portion of the column within the depth of the deepest beam that

frames into the column. There are 3 types of joints in a moment resisting frame:

1. Interior joint-‐ when 4 beams frame into the vertical faces of a column.

2. Exterior joint-‐ when 1 beam frames into vertical face of the column and 2 other

beams frame from perpendicular directions into the joint.

3. Corner joint-‐ when a beam each frames into two adjacent vertical faces of a

column.

Column and Beams Structural Systems

Foundation utilize a combination of bearing walls, columns and piers to transmit

building loads directly to earth. These structural elements can form various types of

substructures.

COLUMN BEAM TIMBER FLOORING

This diagram shows the

components of the building

structure highlighting on the

columns and beams. Timber

flooring were applied on the

first floor with a layer of slab.

The Concrete slabs-‐on-‐grade

supported directly by the

earth at the bottom and

thickened to carry wall and

column loads which is

economical for one and two

storey building in climate

where no ground frost occur.

beam

column

timber flooring

concrete slab

Floor Systems

One Way Slab

Two Way Slab

A rectangular reinforced concrete slab which sp

ans a distance very much greater in one

direction than the other; under these conditions

, most of the load is carried on the shorter span.

A rectangular, reinforced concrete slab having

a span on the long side that is less than twice

the span on the short side and transfer their

loads to all the four support walls.

4.3 Indication of plans

Indication of columns and beams in structural plans

4.4 Distribution in the Structure

To determine whether a slab is one way or two way slab, divide the longer span of the

panel (L) by the shorter span panel (B).

If L/B is greater than or equal to 2, it is a one way slab.

If L/B is lesser than 2, it is a two way slab.

Figure of a one way slab load distribution. It is supported by beams in only 2 sides.

Figure of a two way slab load distribution. It is supported by beams in all 4 sides.

5.0 Conclusion

To conclude our group project, we have gained knowledge which involves structural

theory and basic structural proposal. As going through structural appraisal by

identifying the structural members, we have learnt of basic structure layout drawing for

architectural drawings as well as considerations on beam and column sizing that will

affect the integrity of a structure. Appraisal of structural system is done in ways such as

using assisting tools, thorough research of ways and thanks to our lecturer who has

given out great hand on producing the final products. The report produced gave us an

insight from structural member comprising of reinforced concrete material throughout

the whole building started from the roof beam above throughout the basic skeletal

structure that in the end transfer the load to ground beam. They are connected through

joint and the coordination of structural members allow the load to be transfer uniformly

and effectively. Difference from main supporting structural system such as column to

minor structural stiffener is identified as well in this project.

Last but not least, we would like to thank Mr. Mohd Adib Ramli for his guidance

throughout this project.

6.0 References

1. "Column -‐ Definition and More from the Free Merriam-‐Webster Dictionary". Merriam-‐webster.com. 2012-‐08-‐31. Retrieved 2013-‐07-‐04.

2. Hool, George A.; Johnson, Nathan Clarke (1920). "Elements of Structural Theory -‐Definitions". Handbook of Building Construction (Google Books). vol. 1 (1st ed.). New York: McGraw-‐Hill. p. 2. Retrieved 2008-‐10-‐01. "A cantilever beam is a beam having one end rigidly fixed and the other end free."

3. Bǎnicǎ, Florinel-‐Gabriel (2012). Chemical Sensors and Biosensors:Fundamentals and Applications. Chichester, UK: John Wiley & Sons. p. 576. ISBN 9781118354230.

4. R.J. Wilfinger, P. H. Bardell and D. S. Chhabra: The resonistor a frequency selective device utilizing the mechanical resonance of a silicon substrate, IBM J. 12, 113-‐118 (1968)

5. P. C. Fletcher, Y. Xu, P. Gopinath, J. Williams, B. W. Alphenaar, R. D. Bradshaw, R. S Keynton, "Piezoresistive Geometry for Maximizing Microcantilever Array Sensitivity,"presented at the IEEE Sensors, Lecce, Italy, 2008.

6. The Architects' Journal Existing stadiums: St James' Park, Newcastle. 1 July 2005 9.

7. G. Noselli, F. Dal Corso and D. Bigoni, The stress intensity near a stiffener disclosed by photoelasticity. International Journal of Fracture, 2010, 166, 91–103. Koiter, W.T., On the diffusion of load from a stiffener into a sheet. Q. J. Mech. Appl. Math. 1955, VIII, 164–178.

8. Nilson, Darwin , Dolan. Design of Concrete Structures. the MacGraw-‐Hill Education, 2003. p. 80-‐90.

9. ASCE/SEI 7-05 Minimum Design Loads for Buildings and Other Structures. American Society of Civil Engineers. 2006. p. 1. ISBN 0-‐7844-‐0809-‐2.

10. Avallone, E.A., and Baumeister, T. (ed.). Mark's Standard Handbook for Mechanical

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