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University of Dar es Salaam

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Articles 91 - 120 of 183

Full-Text Articles in Civil Engineering

Trends Of Rainfall And Maize Productivity In Malawi, T Kimaro Jun 2008

Trends Of Rainfall And Maize Productivity In Malawi, T Kimaro

Tanzania Journal of Engineering and Technology (TJET)

Daily rainfall data between 1966 and 2005 across all Agricultural Development Areas (ADDs) in Malawi was investigated to determine changes in selected rainfall characteristics and their impact on Maize productivity. Rainfall indices analyzed included rainfall amounts (annual and seasonal), onset, cessation, dry spells and length of rainy season. Man Kendal’s trend test was applied to the time series of these indices to detect any trends in the time series. Water Requirement Satisfaction Index (WRSI) for maize crop was used to study the spatial-temporal variation of maize productivity and thus its linkage to rainfall. Definition of onset and cessation adopted from …

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Nyumba Ya Mungu Reservoir System Simulation By Using Hec-Ressim Model, Deogratias Mulungu Jun 2007

Nyumba Ya Mungu Reservoir System Simulation By Using Hec-Ressim Model, Deogratias Mulungu

Tanzania Journal of Engineering and Technology (TJET)

This research paper focused on estimating effective water and optimization of the NyM reservoir for storage conservation and hydropower generation. Several models were used in the study: the Rainfall-Runoff model, GFFS was used to fill in missing data, and the HEC-ResSim Model and the NWBM for reservoir system simulation and water balance respectively. The effective inflows to the NyM reservoir were determined using HEC-ResSim model and the NWBM used to check the total water loss in the system. For the reservoir system simulation, the HEC-ResSim model was used to estimate water loss through irrigation abstractions in Kikuletwa and Ruvu reaches …

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Socio-Economic Impacts Of Water Scarcity In Dar Es Salaam, Tanzania, Shadrack Mwakalila Jun 2007

Socio-Economic Impacts Of Water Scarcity In Dar Es Salaam, Tanzania, Shadrack Mwakalila

Tanzania Journal of Engineering and Technology (TJET)

Drought and the resulting low water levels in rivers exacerbate water scarcity conditions in Dar es Salaam city. The result is frequent water rationing in areas served with piped water, sometimes for days or weeks, and low water pressure, which leads residents to resort to other less safe and sometimes more expensive water sources. The frequent and current response to the inadequate piped water supply in Dar es Salaam has been the use of groundwater resources. There are both public and private bore-holes and wells drilling companies in Dar es Salaam.. This paper therefore, presents some socio-economic impacts of water …

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Optimal Utilization Of Timber Poles As Structural Members Of Formwork, Ladislaus Lwambuka Jun 2007

Optimal Utilization Of Timber Poles As Structural Members Of Formwork, Ladislaus Lwambuka

Tanzania Journal of Engineering and Technology (TJET)

Timber poles of the type “Mirunda” are commonly used in East Africa as formwork support structures for casting of reinforced concrete slabs, beams and canopies. It is also widely known that the “Mirunda” poles as structural members of formwork are massively used without any structural consideration and guidance. This common practice has resulted into wastage of natural resources and escalated construction costs. This study has attempted to establish the load bearing capacity of randomly selected “Mirunda” poles through laboratory testing. Using an existing construction site as a case study, the results have been used to establish the actual number of …

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Program For The Analysis Of Plane Trusses, John Makunza Jun 2007

Program For The Analysis Of Plane Trusses, John Makunza

Tanzania Journal of Engineering and Technology (TJET)

The ‘TRAP - TRuss Analysis Program’ can assist engineers in the analysis of plane truss-type structures, as well as prove an excellent basis for understanding the “finite – element” method. The Program is completely menu-driven, with all nodes, elements, and load data entered through an input file. TRAP includes plotting for displaying the truss geometry in its original shape showing all nodes and support points. In the analysis process, firstly the structure data; e.g number of nodes, elements, materials and supports are to be defined. Secondly, element properties and support constraints have to be specified. Finally, nodal global loads are …

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Preliminary Estimates Of Building Cost And The Lowest Evaluated Tender, Harriet Eliufoo Jun 2007

Preliminary Estimates Of Building Cost And The Lowest Evaluated Tender, Harriet Eliufoo

Tanzania Journal of Engineering and Technology (TJET)

The paper has investigated and established to what extent are preliminary estimates of building costs close to the lowest evaluated tender and how geographical proximity influences the variance between preliminary estimate and the lowest evaluated tender. A multiple case study constituting 43 building projects in Tanzania were statistically analysed covering a period from 1995- 1999. Findings reveal a significant variance exists between the quantity surveyor’s preliminary estimate figure and the lowest evaluated tender; and that the variance between the quantity surveyor’s figure and the bidder is small when the proposed building project is geographically closer to the quantity surveyor’s base. …

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Characterization Of On-Road Petrol Vehicle Emissions Patterns In Dar Es Salaam City (Tanzania), Geoffrey John Dec 2006

Characterization Of On-Road Petrol Vehicle Emissions Patterns In Dar Es Salaam City (Tanzania), Geoffrey John

Tanzania Journal of Engineering and Technology (TJET)

Motor vehicle emissions have been identified to be the major source of air pollution in most urban cities. It has serious impact on urban air quality and public health. The Governments of many countries need to adopt stringent vehicle emissions regulations to protect the air quality, the undertaking of which can only be implemented once the problem at hand is known. In the present study, the characteristics of on road vehicle emissions from the selected local ar~as at the city of Dar es Salaam in a developing country for in-use petrol vehicles for urban driving conditions ranging from idling, lOkm/h …

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Impact Of Institutional Framework On Wetland Management In Tanzania, Shadrack Mwakalila Dec 2006

Impact Of Institutional Framework On Wetland Management In Tanzania, Shadrack Mwakalila

Tanzania Journal of Engineering and Technology (TJET)

Wetland loss continues today despite fhe existence of institutions With a specific mandate to manage uvtlands in Tanzania. In reviewing this apparent contradiction, this paper Soes in depth to explore the existing sectors associated with the development and management Of wetlands in the Country. Specifically it focuses on institutional framework a: Village level, Ward level, District level and national level. Among the key sectors consulted includes; agriculture and livestock, wildlife, forestry, fisheries, t'üier resources, lands, minerals and energy. The interest While visiting them was aiming at exploring the existing opportunity With regard to the tulues of the wetlands and their …

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Investigation On Distribution Of Cast Properties On Aluminum Plates Poured By Side Gating Technique, Joseph Runyoro Dec 2006

Investigation On Distribution Of Cast Properties On Aluminum Plates Poured By Side Gating Technique, Joseph Runyoro

Tanzania Journal of Engineering and Technology (TJET)

Casting technologies wllich improve casting yield and intenzal sOllndness of thin wall cast components are of particular interest to industry especially for critical applications. The main aim of fOll1ldries is to achieve castings free from defects at low cost. It hils been thought that pouring casting by side ingate technique improve directional solidification as the metal stays hot for long time in the feeder cum ingate. Experiments were carried alit IIsing a side gating technique to cast a number of 300 mm x 300 mm LMO and LM 25 plates in furall and pepset sand moulds. The thickness used was …

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Determination Of Wind Loads Causing Flutter Effects, Ladislaus Lwambuka Dec 2006

Determination Of Wind Loads Causing Flutter Effects, Ladislaus Lwambuka

Tanzania Journal of Engineering and Technology (TJET)

A new method on the determination Of wind forces by experimental means in a wind tunnel is discussed. The method reported herein is based on the identification methodology Of model parameters under time response (i.e. time domain identification). As a test model, a thin plate Of Cypress wood, elasticully suspended in three degrees Of freedom to represent the idealized form of a classical airfoil, for Which theoretical wind load parameters exist, has been employed. Wind load parameters, experimentally obtained on the test model under the new method, are compared With the theoretical values of classical airfoils. Advantages of the new …

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Geophysical Exploration For Groundwater Resources Potential Over Basement Formations At Kwandolwa And Mwisho Wa Shamba Villages, Korogwe District, Tanzania, Cuthbert Mhilu Dec 2006

Geophysical Exploration For Groundwater Resources Potential Over Basement Formations At Kwandolwa And Mwisho Wa Shamba Villages, Korogwe District, Tanzania, Cuthbert Mhilu

Tanzania Journal of Engineering and Technology (TJET)

In this paper results of geophysical exploration studies to identify potential areas with groundwater resources at Kwamndolwa and Mwisho wa Shamba Villages in Korogwe District have been presented. The resistivity curves of eight sites at the two study areas were obtained using field data measurements made based on the application of a vertical electrical sounding (VES) method. The resisivity values obtained for sites VES-K3 and VES-M2 were found to be 10.9 and 24.0 ohm-m respectively. The interpretation of the resisivity values made for the two sites gave also an indication of the presence of sedimentary rocks composed of sandstone materials …

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Sampling Procedure For Pavement Condition Evaluation Of Local Collectors And Access Roads, David Mfinanga Dec 2006

Sampling Procedure For Pavement Condition Evaluation Of Local Collectors And Access Roads, David Mfinanga

Tanzania Journal of Engineering and Technology (TJET)

Road surface condition evaluation involves the collection Of a lof Of data on different types of distresses. •lie exercise consumes a lot Of resources if the whole road section length is sureeyed and may be prone to errors as a result Of surveyors' fatigue. It is therefore important Io develop n reprevntative sample to be used When road condition manually. This study aimed nt determining sample size for condition evaluation of local collector access roads in urban areas in Tanzania. Two such roads namely l.ufungira and Kilimahewn roads respectively were selected for the study. It is recommended that a section …

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Dar Es Salaam Water Supply Problems And Possible Solutions: Reflections, D Mashauri Dec 2006

Dar Es Salaam Water Supply Problems And Possible Solutions: Reflections, D Mashauri

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions

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Environmental Impact Of Wetland Resources Utilization In Simuyu Basin, Tanzania, Shadrack Mwakalila Jun 2006

Environmental Impact Of Wetland Resources Utilization In Simuyu Basin, Tanzania, Shadrack Mwakalila

Tanzania Journal of Engineering and Technology (TJET)

There is a growing appreciation of the natural functions of wetlands, and the values and different forms of uses that humans attach to them. Wise use and special conservation strategies are therefore needed in order to sustain their productivity. Wetlands are one of the most fruitful areas of archaeological research, and they are the ideal setting in which to study the interactions between physical processes and human actions that encapsulate and exemplify many of the themes of man's impact on his environment. But all these beneficial functions of wetlands seem to be in danger of being lost to draining and …

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Suitability Of Crusher-Dust As Masonry Construction Material, John Makunza Jun 2006

Suitability Of Crusher-Dust As Masonry Construction Material, John Makunza

Tanzania Journal of Engineering and Technology (TJET)

Crusher dust generated at Kunduchi quarries in Dar es Salaam during aggregate crushing is counted as a waste material, and some times it .is disposed away or sold at a cheap price of not more than a quarter of that of sand. A study on the use of the crusher dust as a building material has been carried out in which samples were collected and analyzed for grading (sieve analysis). In additional to that, other samples were stabilized with a small amount of cement, from which bricks were produced and tested for compressive strength. Other bricks were bonded together using …

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Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor Jun 2006

Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor

Tanzania Journal of Engineering and Technology (TJET)

This paper reports on a research project conducted with an objective of identifying and assessing various approaches used by different computer users (Management, System Administrators and end users) in Tanzania to combat computer viruses (CVs), and to assess users' awareness level on CVs. Specifically, the study aimed at assessing the awareness level on CVs to the Tanzanian business community; analyze the socio -economic impact caused by CVs in Tanzania and; assess existing methods, capacity and limitations on controlling CVs in Tanzania. Data was collected using both questionnaires and interview from financial institutions such as NBC and BOT, and telecommunications sector …

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Comparison Of Two Different Transport Models To Predict Sediment Transport: Simiyu River, Tanzania, Case Study, F Mwanuzi1 Jun 2006

Comparison Of Two Different Transport Models To Predict Sediment Transport: Simiyu River, Tanzania, Case Study, F Mwanuzi1

Tanzania Journal of Engineering and Technology (TJET)

This paper presents the results of a study which focused at the spatial and temporal characteristics of sediment transport and deposition in the main river channels and floodplains. Two different numerical models were used to simulate stream flow and to analyze sediment transport and deposition in the river channels: (1) the SMS modules RMA2 and SED2D and (2) the SCALDIS model developed at the Free University of Brussels. Both numerical models contain a two-dimensional hydrodynamic module and a sediment transport module, allowing simulation of stream flow and sediment transport processes in river channels. However, they differ in the following aspects: …

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Overview Of Hydraulics And Simiyu River Sediment Input Into Magu Bay, Lake Victoria, Tanzania, Alfonse Dubi Jun 2006

Overview Of Hydraulics And Simiyu River Sediment Input Into Magu Bay, Lake Victoria, Tanzania, Alfonse Dubi

Tanzania Journal of Engineering and Technology (TJET)

Lake Victoria is experiencing multifaceted environmental and ecological problems. A  study of the problems needs a multidisciplinary approach. to establish the cause-effect relationships. The study focuses on the hydraulics of Lake Victoria's Magu Bay and Simiyu riverine input of suspended sediments and their distribution in the Bay. Sampling in the river mouth and the Bay was conducted aboard an 8m outboard engine wooden boat. Turbidity, currents speed and direction were measured using an "AANDERAA" multi-sensor self-recording current meter model 9 (RCM9). Water depth was measured using an echo-sounder type FISHIN' BUDDY II. Geographical positions of the sampling locations were obtained …

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Quality Of Common Salt In The Tanzanian Market, Kamwanya E Jun 2005

Quality Of Common Salt In The Tanzanian Market, Kamwanya E

Tanzania Journal of Engineering and Technology (TJET)

The quality of edible salts in the Tanzanian market has been studied by comparing the levels of iodine, heavy metals, and non-metals. Among the 19 analyzed local salt samples, only two of them—Kipepeo salt (76.67 mg/kg) and Super salt (79.95 mg/kg)—met the recommended level of iodine as per TBS (Tanzania Bureau of Standards) specifications. Other brands have iodine levels below the TBS specification.

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Degradation Of Waterfront Reinforced Concrete Structures At The Port Of Dar Es Salaam, I Sanga Jun 2005

Degradation Of Waterfront Reinforced Concrete Structures At The Port Of Dar Es Salaam, I Sanga

Tanzania Journal of Engineering and Technology (TJET)

The paper summarises the results of an investigation done on piers at the Dar es Salaam Port. The problem facing these structures and marine facilities is their exposure to aggressive environmental phenomena. The paper presents an investigation of the strength and corrosion of concrete seaport piers so as to determine degradation of the reinforced concrete waterfront structures in the port of Dar es Salaam. For instance the structures at a dhow quay terminal had been in use for about 100 years. The facility was in bad condition as the concrete had been badly damaged due to corrosion. Some of the …

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Cement Oonded Wood Wool Board As A Building Material For Low Cost Housing, A Mrema Jun 2005

Cement Oonded Wood Wool Board As A Building Material For Low Cost Housing, A Mrema

Tanzania Journal of Engineering and Technology (TJET)

This paper gives results of a preliminary study on the properties of cement bonded wood-wool boards manufactured as composites by using wood-wool (excelsior) from podocarpus spp wood species and ordinary Portland cement. Two main parameters were varied during the investigation and these were the width of the wood-wool and the cement to wood-wool ratio. Results show that the optimum mix proportion is three parts of cement to two parts of wood-wool by weight and that a smaller excelsior width gives higher board strengths. The results from tests on flexural strength, compressive strength and tensile strength far exceeded the requirements of …

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Earth Building In Tanzania - Use Of Soil Stabilized Bricks And Blocks, A Mrema Jun 2005

Earth Building In Tanzania - Use Of Soil Stabilized Bricks And Blocks, A Mrema

Tanzania Journal of Engineering and Technology (TJET)

This paper presents experimental results of investigations done on the use of stabilized earth (soil) for the manufacture of bricks and blocks. The soil used was clayey sand of low plasticity. Two types of stabilizers were used to make stabilized bricks and these were cement and a combination of cement and lime. Different stabilizer proportions were employed. Results of tests carried on these bricks at 28 days indicate an optimum mix proportion of 7% cement if cement is used alone and an optimum mix proportion of 5% each if a combination of lime and cement is used as a stabilizer. …

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Low Cost Slab Manufactured From Masonry Slab Elements, John Makunza Jun 2005

Low Cost Slab Manufactured From Masonry Slab Elements, John Makunza

Tanzania Journal of Engineering and Technology (TJET)

The construction of bungalow houses requires sufficient space to accommodate all the requirements as per the client’s wish. The idea of low-rise or high rise buildings is very remote for most of the people due to the high costs of construction involved. Much of the said cost is due to the concrete floor slab as it consumes a bigger portion of concrete material when compared to beams and columns. In this paper, a study presented is on a new form of voided slab constructed from masonry slab elements that do not utilize formwork and consumes less concrete material. The slab …

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Ceramic Properties Of Chimala Kaolin Clay, Leonard Akwilapo Jun 2005

Ceramic Properties Of Chimala Kaolin Clay, Leonard Akwilapo

Tanzania Journal of Engineering and Technology (TJET)

The physico-chemical properties of kaolinite clays occurring in abundance near Chimala were studied with a view of finding out their suitability in sanitary ware production. The viscosity of the clay was found to be within the range acceptable in industrial application (≤ 500 cp for 70% solids), enhancing its prospects for the manufacture of slip cast shapes with satisfactory properties. The chemical composition of the clay reveals a high content of Fe₂O₃, 1.48%, which is expected to affect the translucency and colour of the finished ware. However, such quantity would not have detrimental effects in the production of sanitary ware. …

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Hydrographic Aspect Of Chole Bay, Mafia Island, Alfonse Dubi Dec 2004

Hydrographic Aspect Of Chole Bay, Mafia Island, Alfonse Dubi

Tanzania Journal of Engineering and Technology (TJET)

Mafia has been a port on the monsoon trade routes from the Arabia to Sofala for almost 2000 years. The Island has not changed significantly since ancient times and retains a traditional culture of fishing and subsistence agriculture. By 1991, development of tourism on the Island seemed very slow. Factors limiting the number of visitors include lack of adequate travel connections between the island and the mainland, and inadequate and poor hotel services. Currently, accessibility to Mafia Island has improved. Mafia Island can now be reached by air in addition to the traditional sea travel. However, the Island does not …

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Assessment Of The Accuracy Of Approximate Methods In The Analysis Of Plane Frame Structures, I Rubaratuka Dec 2004

Assessment Of The Accuracy Of Approximate Methods In The Analysis Of Plane Frame Structures, I Rubaratuka

Tanzania Journal of Engineering and Technology (TJET)

pproximaic methods of analysis are widely used in the analysis OJ' frames for preliminary design due to their simplicily as compared to exact analysis meth o ds Ough they a re nol as accurate. In this paper. the methods Of hinges and portal frame are described and have been used to analyze a statically indeterminate frame by taking inro account the bending stiffness of the frame members. The obtained results are comparable Io the magnitudes of forces determined by exact methods Of analysis.

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Review Of The Product Development Process And Information Flow In The Manufacturing Industry: Problems And A Possible Wav Forward, E Opiyo Jun 2004

Review Of The Product Development Process And Information Flow In The Manufacturing Industry: Problems And A Possible Wav Forward, E Opiyo

Tanzania Journal of Engineering and Technology (TJET)

No abstract provided.

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Importance Of Structural Fire Protection In Reinforced Concrete Buildings: A Case Study Of Ex-Nasaco Building In Dar Es Salaam, I Rubaratuka Jun 2004

Importance Of Structural Fire Protection In Reinforced Concrete Buildings: A Case Study Of Ex-Nasaco Building In Dar Es Salaam, I Rubaratuka

Tanzania Journal of Engineering and Technology (TJET)

Reinforced concrete is concrete that is internally reinforced with steel bars or mesh. This gives rhe malerial the compressive strength of concrete along wilh the tensile strength Of steel. Reinforced concrete does not perform well under fire conditions as it spalls and loses strength. Heating Causes a failure Of the bond between concrele and sleels bars and this results in reduction of strength of concrele. Strength of concrete decreases With increase in temperature and increase With time. In order to provide fire resistance to structural components/elements in buildings, it is important Io consider the type of aggregates to be used. …

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Field Evaluation Of Soil Physical, Chemical And Hydraulic Property Changes Caused By Surface Water Application: A Case Study Of Ruaha-Mbuyuni Irrigation Scheme, Iringa, Tanzania, A Tarimo Jun 2004

Field Evaluation Of Soil Physical, Chemical And Hydraulic Property Changes Caused By Surface Water Application: A Case Study Of Ruaha-Mbuyuni Irrigation Scheme, Iringa, Tanzania, A Tarimo

Tanzania Journal of Engineering and Technology (TJET)

The conventional metering. pyepa.vmen,' and estimates have been used in power utilities industries. The svslen,'s hare experienced many problems such as power tampering, bill tampering, ./åiluve ro receive invoices by poner unlity customers and so on. Different technologies have been investigated To overcome the problems and recently it has been realized that remote 'nonitoring sysle•ns through powerline channel is a solution offhese problems in Tanami". However. 'he powerline network has been used for electrical power IO use i,' for implementation of remote monitoring: network must be setup and has to be modeled to accommodate communications. The contribution has analyzed 'he …

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Introduction Of Seismic Resistance Features In The Construction Of Buildings In Tanzania, I Rubaratuka Jun 2004

Introduction Of Seismic Resistance Features In The Construction Of Buildings In Tanzania, I Rubaratuka

Tanzania Journal of Engineering and Technology (TJET)

Available dara indicates that a greater part of Tanzania lies within a seismic region. to date most Of the buildings in the country have been designed and constructed without considering seismic loads. In addition no design codes have been developed to guide the seismic design for buildings and other related structures in Tanzania. This paper outlines the basic design concepts, which are useful during the design of seismic resistant buildings before the seismic design code is developed and adopted in Tanzania.

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