cdr-sample_-civil_project

8/7/2019 CDR-Sample_-civil_project

1/4

CDR-Sample

INTRODUCTION:

In the second episode I would like to share a design project which I have completed about

two months back. This project was of a marriage hall given to us by our client XXXX. Inthis project I was working as a Design engineer and the concrete design was assigned to

me by my head of department.

BACKGROUND:

This marriage hall was constructed on right bank of Lahore Canal near Doctors hospitalLahore. It comprises of 3 story building where 2 stories (ground and first floor) are of

concrete structure and second floor is of steel structure. Each story height is 10ft. This

hall is 60 ft wide and 230 ft in length. So it has a covered area of 36800 square ft. per

floor. It was designed for a capacity of 1000 person per floor.

since our company is specialized in pre-stressed concrete products; if a client wants to

use our pre-stressed roofing system then we provide him the facility of designing thewhole structure as an incentive. In this marriage hall Double Tee planks were to be used

so we provide him the facility of complete structural design also.

Sale department send this design request to Director Design and he assigned this project

to me. I had to design all the structural components of the frame structure that includes

column footings, columns, beams and roofing system i-e Double Tee planks. Heexplained me the design requirements of the client and also advice me to have a sitting

with the client.

I had a detailed meeting with the client where I discussed all important issues regardingdesign requirements of client. I came to know that clients main requirement was that

each floor should accommodate at least 1000 people at a time along with furniture and

the design should be economical.

My particular work included calculation of design loads, analysis of structure using

software(Staad-pro), designing of various structural components i-e column footings,columns, plinth beams, bracing beams, column etc according to ACI318-05, testing and

verifying my design, giving instructions to draftsman for drawings, checking of drawings

and finally issuing of drawings for approval by our head of department.

PERSONAL WORKPLACE ACTIVITIES:

First of all I studied the architectural design of the marriage hall that was provided to me

by the client and found it a 3 storied frame structured building. I also studied the

Geotechnical report provided by the client. I found that the soil was clayey soil with abearing capacity of 0.9 tons per square foot.


2/4

After finalizing the layout plan I started my design work. I calculated the seismic and

wind loads according to Building Code of Pakistan (Seismic Provisions-2007) and loadcombinations according to ACI389-05. Following were the Design criteria:

Firstly I worked on material properties. I decided to have Concreted CompressiveStrength: For foundations = 3000 Psi, For columns = 3750 Psi and For main beams

= 3500 Psi. Steel Reinforcement: Yield strength of deformed bar = 60,000 Psi,

Modulus of elasticity = 29000 Psi. Soil: Unit weight = 110 Pcf, Safe allowable bearingcapacity = 0.9 Tons per square ft.

I considered the following load: Dead Load: Unit wt. of concrete = 150 Pcf., Live Load:

Live load on floor = 80 Psf. This live load is mainly in the form of public gathering.Seismic Loads . The seismic loads are as per Building Code of Pakistan (Seismic

Provisions-2007).

The Seismic Provision are compatible with the UBC-1997, the American ConcreteInstitute ACI318-05, American Institute of Concrete Construction ANSI/AISC341-05,

American Society of Civil Engineers SEI/ASCE7-05 and ANSI/ASCE7-93.

Design Base Shear: The total design base shear in a given direction shall be determined

from the following formula: V = Cv.I.W/R.T. Wind Load: Basic wind speed

of 80mph is taken and found to be governing. Design wind pressure was calculated by thefollowing formula:

P = Ce.Cq.qs.Iw

Load Combinations:-

Following are the load combinations used according to ACI318-05.

U = 1.4(D + F).

U = 1.2(D + F + T) + 1.6(L + H) + 0.5(Lr or S or R).

U = 1.2D + 1.6(Lr or S or R) + (1.0L or 0.8W).

U = 1.2D + 1.6W + 1.0L + 0.5(Lr or S or R).U = 1.2D + 1.0E + 1.0L + 0.2S.

U = 0.9D + 1.6W + 1.6H.

U = 0.9D + 1.0E + 1.6H.

Where,

U = required strength to resist factored loads.

D = Dead load.

F = Load due to weight and pressure of fluids.

T = Cumulative effect of temperature, creep and differential settlement.


3/4

L = Live load.

Lr = Roof live load.

S = snow load.R = Rain load.

E = Load effect of earth quake.

W = Wind load.H = Loads due to weight and pressure of soil.

After that I started to make model of the structure using Staad-pro. After making modelloads were applied and load combinations were specified. Then, I gave command of

analysis and after having analysis; results of reaction forces and bending moments are

obtained.

I then identify critical load combinations for every member and node. Then comes the

design work. I always started my work from footing. For footings unfactored load

combinations are used and for other structural components factored load combinations

are used.

I have made design flow sheets on Excel for all structural components except columnaccording to the code design criteria given in ACI318-05 and design the whole building

using those sheets. Columns are designed using PCACOL Version 2.30 software.

Column section, reinforcement and material properties are provided to the software along

with shear force and bending moment. Interaction diagram shows whether it is a safedesign or need any revision.

After finalizing the design I gave instructions to draftsman about the drawings. I gavethem handmade sketches of all the structural components showing reinforcement details

for their assistance. After completion of drawings I checked them according to my design

and issue these drawings for approval by my Head of Department.

For my own satisfaction I also counterchecked my design results by analyzing the same

model using ETAB and results were compared. I found the same results of shear forcesand bending moments by both soft wares.

I also faced some problems. One of the problems was about the dimensions of the

footings of columns as the site is situated in urban area so less space is available allaround the building for rectangular or square footing. As the columns are located at the

edge of property line so one sided footing is possible only. In this type of footing the is

always a possibility of overturning of the column as the line of action of load and that ofsoil pressure are at some eccentricity with respect to each other.

I discuss this matter with my senior and he suggested connecting the opposite columnswith a raft beam so that stability of the building would be ensured. Another problem was

that the footing was too wide I gave a suggestion that the ground floor and first floor

should be design as concrete structure and second floor as steel structure to reduce the

load of the building. This suggestion was accepted by the client.


4/4

I always prefer to work in a team. My team is always supportive to me. Whenever I face

some problem I prefer to consult it with my senior and he is always there to help me. Myassistants are also very efficient in performing the tasks which I assigned to them.

SUMMARY:

This project has enhanced my professional knowledge. Whenever I face some problem I

prefer to consult it with my senior or try to get solution of that problem by reading relatedbooks or internet.

cdr-sample_-civil_project

Documents