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Int. J. Struct. & Civil Engg. Res. 2012 Muhammad Saiful Islam et al., 2012

EVALUATION AND COMPARISONOF BUILDING CONSTRUCTION TECHNOLOGIES

IN TWO MAJOR CITIES OF BANGLADESH

Muhammad Saiful Islam1*, Hasibur Rahman1 and Md. Ashrafuzzaman1

The study considers the building construction technologies available in Bangladesh. It has beencarried out to evaluate the existing situation of construction projects in the country and its aim toevaluate the current situation and make a comparison between the cities, i.e., Dhaka, the capitalcity and Sylhet, the fast rising city but located at the periphery of the country. The projectsinvestigated in this study include both residential and commercial buildings and the survey workswere done by visiting different construction sites and collected all possible and related informationthrough interviews and questionnaires of the workers and engineers. Since technology isimportant in contrast of time, cost and quality, it is urgent need to evaluate the condition whichwill help for the respective authorities to take initiative for introducing modern technologies inconstruction industries. Study shows that periphery areas are far away from modern constructiontechnologies compare to that of capital city, although the capital city also has so many deficienciesto use automation technology compare to that of modern word. Thus proper mechanization andimplementation of modern building construction techniques would bring significant impact inbuilding construction by improving its quality with reducing time and cost.

Keywords: Building construction, Modern technology, Questionnaires, Dhaka

1 Department of Civil and Environmental Engineering, Shahjala University of Science and Technology, Sylhet, Bangladesh.

*Corresponding Author: Muhammad Saiful Islam, [email protected] [email protected]

INTRODUCTIONBuilding construction is the process of addingstructure to real property. The vast majority ofbuilding construction jobs is small renovations,such as addition of a room, or renovation of abathroom. Often, the owner of the property actsas laborer, paymaster, and design team for theentire project. However, all building construc-tion projects include some elements in

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Int. J. Struct. & Civil Engg. Res. 2012

Research Paper

common-design, financial, estimating andlegal considerations. (Tucker, 1991).

Salam et al. (1999) studied that inBangladesh, all types of civil engineeringworks, including infrastructure, low and high-rise buildings, defense installations such asfire protection and earthquake resistant,environment protection and local/domesticconstruction are being constructed to use

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traditional and modern technology. Bangladeshis a densely populated developing country. Tomeet the continuous housing demand,construction works are rising firstly. Develop-ments in building construction and inconstruction industries have a significant rolein the overall development of a country. Soconstruction industry of any country requiresserious attention for further improvement.

In common with other developing countries,demographic changes in Bangladesh areresulting in massive migrations of people fromvillages to urban areas. The capital city ofDhaka, Bangladesh is facing severe over-population. However, even though governmentspending is increasing, it is not nearly enoughto solve the housing problems and, therefore,over the last 10-12 years, private companieshave stepped in to initiate real estate businessthrough the construction and sale of middle tohigh-rise apartment buildings. The mainreasons for high-rise rather than low-riseconstruction are scarcity of land and landprices (Salam et al., 1999).

Photios and Robert (1988) performed a studyto assist the construction and manufacturingindustries in becoming more efficient and costeffective through the introduction and broad useof new technologies. They found that approxi-mately 50% of construction costs in lightindustrial and commercial building construc-tion are related directly to enclosure andstructural systems. Since these systems arecommon among industrial buildings, theidentification and adoption of effective andefficient technologies in these areas is a majorstep toward improving quality, reducing costs,and expediting schedules.

The cost of building construction has risendramatically in recent years worldwide.Excessive construction costs have eroded thecompetitive position of the US constructionindustry and are having a similar impact onthe manufacturing industry by preventing it frombuilding new plants and modernizing existingones. A large number of projects have beenabandoned because the cost of constructionis a large component of a corporation’s cashflow. The decline will continue until constructionfirms lower costs and improve techniques tothe point where growth is worth the risk andinvestment. An effective solution to theseproblems is the introduction of new techno-logies that enhance the quality of the buildingproduct, increase construction efficiency, anddecrease costs. For new technologies to beincorporated in building construction, however,they must first be identified and evaluatedduring the project design phase and theconstruction planning phase (http://en.wikipedia.org/wiki/Construction# Build-ing_construction).

Anthony C Webster (1993) reported that“the modern technologies available inconstruction arena like as the elevator systemwhich is operated by one worker stationed atthe ground floor, keeping him more comfor-table and safe than he would be inside the lift.His only jobs are to tell the lift’s computer controlsystem which floor to take a given load ofmaterial to, and to direct the lift to pick up anymaterials that are ready to be sent to theground floor. The system is fully automatedwhere work is performed at a computerterminal, which displays an animated pictureof the lift’s current location, the load inside it,and the status of the stacking area at each floor.

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There is a television screen next to the terminaldisplays the interior and doors of the lift and ifthere is no room on a given floor to stackpallets, the computer terminal displays a bluebox on the floor next to the elevator and willrefuse to load any more pallets designated forthe floor. Boxes waiting to be picked up fromhigher floors are shown in red”. Such type oftechnologies are available in developedcountries where construction works aredominated by machine rather than man andwhich increases the construction productivity,quality and reduces the time which rarelyavailable in Bangladesh.

In addition there are many constructionrobots is used in Japan (Levy, 1990), forautomated concrete finishers, steel weldingmachines, and facade inspection systems.Besides for floor finishing robots are used inJapan but the effectiveness for example, isreportedly similar to American walk-behindsystems, and are “an order of magnitude” lesseffective than American riding trowels (Tucker,1991). Tucker (1991) reports that generally theequipment “has not been successful,” at leastto increase productivity.

PROBLEM STATEMENT ANDAIMSExtreme a large number of limitations exist fordeveloping and improving the buildingconstruction management in Bangladesh dueto technology constrains. The constructionpractice no doubt can be improved by adoptingadvanced technology and changing over tomechanized system for construction and giveto efficient management. However, consideringthe resource constrains and conditions ofavailable resources and adoption of appro-

priate of technology, in this content, theobjectives of present works are to study thepresent status of building constructiontechnologies in Sylhet and Dhaka city ofBangladesh, and to make a comparisonbetween the cities for finding the technologylag of peripheral cities of the country. Besides,the study will show the capabilities ofBangladeshi construction organizationsworking in the country depending onconstruction equipments and technologies.

METHODOLOGYThis study includes all the details survey relatedto building construction techniques andtechnologies such as the process performed,equipments used, techniques followed inconstruction sites, etc. There are many waysto get information and collect data for anyresearch work. Surveys are one of the majortools for getting the information. The mostcommon survey methods are: LiteratureSearch, Talking with Responsible People,Focus Group Discussion, Telephone Survey,Post Mail Survey, and Preparation ofQuestionnaire. A literature search involvesreviewing all readily available materials. Thesematerials can include internal companyinformation, relevant trade publications,newspapers, magazines, annual reports,company literature, on-line data bases, andany other published materials. Talking withresponsible people is a good way to getinformation during the initial stages of aresearch project that can be used to gatherinformation that is not publicly available, or thatis too new to be found in the literature. A focusgroup is used as a preliminary researchtechnique to explore people’s ideas and

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attitudes. A group of 6 to 10 people meet in aconference-room-like setting with a trainedmoderator. Their disadvantage is that thesample is small and may not be representativeof the population in general. Telephone surveysare the fastest method of gathering informationfrom a relatively large sample (100-400respondents). The interviewer follows aprepared script through that telephone call isessentially the same as a written questionnaire.Mail surveys are a cost effective method ofgathering information. Because there is nointerviewer, there is no possibility of interviewerbias. The main disadvantage is the inability toprobe respondents for more detailedinformation. Preparation of questionnaireincludes the question types, reliability andvalidity, strength and weakness of thequestions, etc. Questionnaires are printed listsof questions used to find out what people thinkor feel about an issue, product or service. Theycan be filled in away from the researcher inthe form of a self-administered, group-administered or postal questionnaire.Questionnaires can provide quantitative datausing close (or fixed-response) questions,where the respondent is presented with anumber of alternative responses to a questionand asked to mark the one that they feel ismost appropriate (Oppenheim, 1992).Qualitative data can be gathered using open(or free-response) questions to whichrespondents are asked to write their ownanswer (Oppenheim, 1992). However, closedquestions are more specific than open ones,communicate the same frame of reference toall respondents, and well designed responsecategories can more accurately detectdifferences among respondents (Converse

and Presser, 1986). Postal questionnaires canbe a cheap and effective method for gatheringdata from a large number of widely dispersedpeople (Oppenheim, 1992). Strength is that,because the researcher is not present whilethe respondents make their answers, datacollected using questionnaires is free of anyinvestigator effects (Oppenheim, 1992). Theweaknesses of postal questionnaires arerelated to the fact that they may be filled in awayfrom the researcher. There has been muchargument over whether text should be left andright justified (all lines are made an equal lengthby varying the spacing between words) or justleft justified (word spacing is consistent andline endings are ragged). It seems that thereis little difference between fully justified and leftjustified text in terms of legibility, reading speedor comprehension (Hartley, 1994). However,Hartley (1994) argues that there areindications that left justified text might be morehelpful for less able readers, be they youngchildren or elderly people. Questionnaires areversatile, allowing the collection of bothsubjective and objective data through the useof open or closed format questions. Moderncomputers have only made the task ofcollecting and extracting valuable materialmore efficient. However, a questionnaire is onlyas good as the questions it contains. Themajority deal with making the questionnaireunderstandable and free of bias. Mindfulreview and testing is necessary to weed outminor mistakes that can cause great changesin meaning and interpretation. When theseguidelines are followed, the questionnairebecomes a powerful and economic evaluationtool. Most of the mentioned characteristics andprinciples of questionnaire design were

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followed during the design of selected

questionnaires for the study. After survey, it is

very important task how to tabulate and then

analyzed the collected data. In this study data

was firstly tabulated in a easy tabular form and

then analysis by percentage to make it easy

to understand and perception of real field

condition. In addition, data also presented

graphically like bar chart and discussed in

details. Finally, a brief conclusion was made

to evaluate the present scenario of Bangla-

deshi construction arena.

RESULTS AND DISCUSSIONAnalysis of survey data and interpretation is

these is the most important task of the thesis.

The main objective of the thesis work was

totally depends on the accuracy of the data,

analysis and interpretation. To analyze the data

tabular, graphical representation and method

of percentage were adopted. Survey data

includes three types of data, i.e., site infor-

mation, construction procedure, and quality

control. These data are collected by survey from

12 different building construction sites in Sylhet

and 14 different building construction sites in

Dhaka city. The surveyed sites were selected

by using simple random sampling technique.

All the data were interpreted by numerical

value and graphical representations are made

with the help of Microsoft Excel. To realize the

general practice in the field of construction,

there was no alternative of field survey. Total

26 construction sites are visited in Sylhet and

Dhaka city. Those sites includes the residen-

tial, commercial and both the combina-tion of

residential and commercial buildings, low rise

and high rise buildings, the building having the

frame system of beam slab or flat plate system

in various construction areas.

Table 1 shows what type of building con-

struction sites were surveyed and visited in

both sampling areas. In capital city Dhaka,

there were eight residential, five commercial

and one multipurpose ongoing building

construction sites were surveyed in which

thirteen are high rise means above six storied

and one low rise means up to six storied.

Besides, in peripheral city Sylhet, there were

three residential, seven commercial and two

multipurpose ongoing building construction

sites were surveyed in which seven were high

rise and five were low rise.

If the construction sites are classified

according to percentage, 58% high rise

building is covered in Sylhet and 93% that of

in Dhaka city. In other words, it can be said

that the construction of high rise building is

more than the construction of low rise building.

Table 1: Types of Building Surveyed in Dhaka and Sylhet City

City Type of Building

Residential Commercial Multipurpose High-rise Low-rise

Dhaka 8 5 1 13 1

Sylhet 3 7 2 7 5

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The first step of the construction work is toset the perpendicular line for the trenching andexcavate the site perpendicular to the groundlevel. To achieve these objectives the layouttechnique has been adopted to do the taskaccurately. There are various methods for thelayout technique. From Figure 1, it indicatesthat use of the traditional method of layouttechnique is practiced rather than using themodern method. It may be for the inadequacyof the equipment as well as shortage oftechnical personnel. Recently the constructionworks became more machine related; the useof the theodolite is increasing in Dhaka areafor the layout technique.

Figure 1: Layout Techniques of BuildingConstruction Sites

faced these problems in those areas. Thewhole assembly was submerged in the fluid tobe pumped. Submersible pumps were easilyprimed (removing air from the suction line)compared to other alternatives. Table 2,indicates how popular the pumping method ofdewatering in our country. Most of theconstruction site in Dhaka uses this methodfor dewatering where in Sylhet, fewer con-struction site used this pump for dewatering.

Table 2 also shows that the excavation workis mainly done by manpower all over thecountry. It actually depends on the constructionarea of work. For small area, manpower issuitable rather than machine. But for large areaof construction, machine is used for excava-tion to save the time and money. In case ofsoil compaction the backfilling is also most ofthe case done by manpower rather thanmachine. Since, manpower is available andcheap, it is quite good but in terms of time it isthe drawback of Bangladeshi construction.Table 2, indicates traditional method ofmanpower is using in both areas and only onesite of Sylhet and 3 sites of Dhaka are usingmachine equipment for backfilling.

Aggregate crushing is generally done bymachine for stone chips and brick chips. Butfor small and economic construction, brickchips are produced by crushing the brick withthe help of daily labor. The crushing of stone

Table 2: Technology Used in Foundation Works

City Dewatering Tech. Earth Excavation Backfilling Tech.

Pump Use Manpower Machine Manpower Machine Manpower

Dhaka 12 02 04 10 03 11

Sylhet 07 05 01 11 01 11

Water logging problem is a commonproblem in construction site. Mainly for deepexcavation the water logging problem arises.Study shows that, among 12 different buildingconstruction sites in Sylhet, only 2 sites werenot faced water logging problem and in Dhakacity, only 3 sites were not faced water loggingproblem. Most of the construction sites are

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aggregate is mainly done at aggregatecrushing plant where the brick chips arecrushed by the crusher at site from bricks. Afew small farms still use day-labor for crushingbrick chips which is cheaper but timeconsuming. For rapid construction, mechanicalcrushing facility is necessary. Mechanicalcrushing of aggregate is increased day by dayas in Table 3, 83% sites crushed the aggregateby mechanical means where only 17% by day-labor in Sylhet city but Dhaka is clearly aheadand 100% sites are using machines. Inaddition, the table also represents that no siteswere used mechanical screener for producingwell graded aggregate at site in Sylhet city.They ordered the specific size and type ofaggregates which was screened at the plantand only 10% sites at Dhaka screened theaggregate at their site by revolving method.Regarding aggregate washing which is verymuch important for gaining strength byremoving foreign materials, it is evident that inour survey sites, most of them used manuallywashed aggregate.

Type of Concrete Use

There are two types of concrete was availablein Bangladesh. Ready mixed concrete issuitable for large concreting and the mixed atsite concrete was suitable for small volume ofconcrete. During the slab and beam castingfor medium to large construction site, ready

mixed concrete is used; while for column andlintel casting mixed-at-site concrete was used.From Figure 2, it represents that among 26different building construction sites, 24 of themused the concrete mixed at on site in Sylhetand Dhaka city, and only 2 of the sites wereused ready mixed concrete for large volumeof concreting which are located in Dhaka. Thewhole scenario represents the warning signof how far away the Bangladeshi constructionsfrom modern world.

The use of admixture was important for thewater proofing and workability properties ofthe concrete. Normally the admixture was usedfor these two reasons. Though the use ofadmixture was not governed but the situationis progressing day by day. As the water cement(w/c) ratio was not maintained correctly the useof admixture was important for gaining theadequate strength of the concrete. From Table4, it shows that 100% projects of Dhaka city

Table 3: Preparation of Aggregate

City Stone Crashing Tech. Screening Machine Washing Tech.

Mechanically (%) Manually (%) Use at Site (%) Not Use at Site (%) Mechanically (%) Manually (%)

Dhaka 100 00 10 90 07 93

Sylhet 83 17 00 100 00 100

Figure 2: Type of Concrete Usedin Construction Sites

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Table 4: Concrete Preparation and Use

City Admixture Use Concrete Mixing Tech. Concrete Compaction Tech.

Yes (%) No (%) Automatically (%) Manually Driving Machine (%) Mechanically (%) Manually (%)

Dhaka 100 0 70 30 100 0

Sylhet 17 83 20 80 100 0

used admixture for concreting which indicateswhenever the w/c ratio is not maintainedaccurately, use of admixture is needed but 83%sites do not use admixture in Sylhet. The tablealso depicts that the rate of using automaticconcrete mixture machine is increasing inDhaka, i.e., 70% of the projects producedconcrete through auto machine but in Sylhetthe situation is not at satisfactory level becausethey depends on manually driven mixturemachine (i.e., 80% case). However, forcompacting concrete after placing intoformwork all the projects of both cities are usingvibrator which is really good sign.

Lifting device was used for material raisingor cumbersome objects. Sometimes concretebuckets were used with the roof hoist andtower hoist. They are specially designed formass placement of concrete in large projects.From Table 5, it is clear that 80% transportingof materials was done by mechanical meansin Dhaka city and 100% is done by manually

in Sylhet city. It shows the use of machine wasincreasing day by day in building constructionworks in Dhaka areas. The table alsoillustrates, the concrete pumping machine isused all sites of Dhaka but only 20% sites atSylhet was used the technology. Passengerlift has their stable performance, reliable,safety, easy transportation and strong adapta-bility can enhance work efficiently and reduceworks labor intensity. It is suitable for thevertical transport of people and constructionequipment. Above table, shows among 26different building construction sites in Sylhetand Dhaka city, only 3 sites used thepassenger lift in Dhaka city and 23 sites didnot use these equipment which meansregarding technology based construction thecapital city is introducing modern techniquesbut at periphery areas construction is actuallydepends on the ancient means.

It is used for removing or displacing mortaror concrete from steel sheet. The use of

Table 5: Technology Use in Different Purposes

Materials Lifting Tech. Concrete Lifting Machine Passenger Lift

City Mechanically Manually Pumping Other means Use at Not use

(%) (%) Machine Use (%) (%) site (%) (%)

Dhaka 20 80 100 00 80 20

Sylhet 00 100 20 80 00 100

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Table 6: Equipment use in Grinding, Welding, Fabricating

City Grinding Machine Welding Machine Steel Fabricating Machine

Use at Sites Not use at Sites Use at Sites Not use at Sites Use at Site Not use (Manually)

Dhaka 14 0 8 6 14 0

Sylhet 1 11 12 0 11 1

grinding machine is more popular Dhaka than

Sylhet. Table 6 depicts, all the projects of

Dhaka used grinding machine to smooth

surface but in Sylhet its use was very limited

to only single project. In case of using welding

machine, among 26 building construction

sites, 8 sites used the welding equipment in

Dhaka city and all sites of Sylhet used the

machine. The cutting of reinforcement was

necessary due to erect in right place afterformwork was done. The mechanical cuttingwass common where the bending of thereinforcement was done by manually. The tableabove shows the evidence of 100% sitescutting the steel by mechanical means inDhaka city and 92% that of Sylhet city. It showsthe use of such machine is increasing day byday in building construction works in ourcountry.

Table 7 shows that steel boards for form-work was used at all the projects of Dhaka

which represents the sign of quality construc-

Table 7: Materials Used in Formworks and Scaffolding

City Formworks Scaffolding

Steel board (%) Wooden board (%) Both (%) Metal (%) Bamboo (%) Both (%)

Dhaka 100 00 00 57 29 14

Sylhet 08 75 17 00 92 08

tion regarding shape and size of structure. But

construction sites in Sylhet city, only 8% they

were used the steel shutter and 75% sites used

the wooden board. The table also depicts that

for scaffolding our construction sectors still

depends on bamboo specifically the remote

cities like Sylhet totally depends on bamboo

(92%). However, the capital city more advance

than Sylhet for using metal scaffolding rather

than bamboo and 57% projects used metal

scaffolding.

Curing system

The traditional method of curing in Bangladesh

for beam and slab is ponding, for column it is

the wet gunny bag and for the plastered

surface, spraying which was done by pipes or

other equipments. Figure 3, represents that

among 26 different building construction sites,

most of the sites were practicing ponding,

spraying and wet gunny bag method but the

method of fogging was not practicing.

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Figure 3: Type of Curing SystemAvailable in Construction Sites

CONCLUSIONThe study has been conducted by collectinginformation through field study from variousbuilding construction farms and craftsmanengaged in various construction works. Someowners of the construction companies have anopinion that cost of mechanized constructionand modern construction techniques in buildingconstruction will be more in a country of cheapmanpower like Bangladesh. Through a fieldsurvey covering construction technology, stateof construction techniques and constructionequipment being used, these constructiontechnologies are revealed to be smooth andefficient building construction practice. Thestudy concluded that the overall constructionsin Bangladesh is yet beyond the moderntechnology, although the capital city areintroduced some of the modern facilities butremote but vastly growing city like Sylhet isabsolutely rising under tradition methods ofconstruction. In addition, the mechanization forconstruction has not yet reached at satisfactorylevel like steel fabricating, bending, concretemixing, placing, compacting, curing, etc.,should be fully mechanized for saving time,ensuring quality and serving economicconstruction. Planned utilization of equipmentat different stages of construction is a

necessity for faster and quality construction.However, these equipments should be ownedby specialized organization and provided tobuilders through a back system of manner tominimize the idle time. Construction methods,techniques and safety being practiced have avast scope for modernization and improve-ment.

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6. Oppenheim A N (1992), QuestionnaireDesign, Interviewing and AttitudeMeasurement.

7. Photios G loannou and Robert I Carr(1988), “Advanced Building TechnologyMatrix System”, Journal of ConstructionEngineering and Management, Vol. 114,No. 4, pp. 517-531.

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