This thesis entitled "Comparison of cost and suitability for the use of raft and pile foundations for construction" presented by Md. Shakil Hossen ID in the Department of Civil Engineering, Daffodil International University, has been accepted in satisfactory partial fulfillment of the requirements for the degree of B.Sc. In-depth knowledge and great interest our supervisor in the field of "Comparison of the cost and suitable for the use of Raft and Pile Foundation for Construction" to realize this thesis.
Hussainuzzaman, Head, Department of Civil Engineering, for his kind help to complete our project and also to other faculty member and the staff of Civil Engineering department of Daffodil International University. Raft and pile foundations are becoming more and more popular in the construction of multi-story buildings, especially when the bearing capacity of the foundation is low and the column load is very high. There are mainly two types of foundation discussed here, where it is assumed that the bearing capacity of the soil and the value of SPT value N are the same for the two foundations.
Many types of research papers have appeared in the era of raft and pile foundation design, but no one has discussed which foundation construction is more affordable and long lasting. 𝐼𝑥 Moment of inertia about the X-axis 𝐼𝑦 Moment of inertia about the Y-axis 𝑒𝑥, 𝑒𝑦 Coordinate of the resultant force.
RAFT FOUNDATION COST ANALYSIS
COST COMPARISONS BETWEEN PILE AND RAFT FOUNDATION
INTRODUCTION
BACKGROUND OF THE STUDY
Advances in technology within the current era have led to several changes in the direction of the poles. In this case, the method, known as the conventional method, is like a slab at the bottom of a column; the raft foundation is then divided into strips in the middle of the column line and the force system in each strip is adjusted to balance. ACI is one of the most widely used and well-known raft foundation analysis methods, the Flexible Approximate Method (ACI Committee 336), which is mainly based on the analysis of Schleicher (1926).
A further finite difference method (Deryck and Severn 1961, .. Bowles 1974) wherever the raft is modeled as a large flat plate in an elastic medium. In 1996, Liou and Lai presented a special structural design for the Raft Foundation as a reinforcement of the floor beams from the castle. Morshed in 1996 and Sutradhar in 1999 distinguished between the finite element method and the performance of comparative analysis. ACI method and conventional method used Ahmed dense shell material for Raft foundation.
His research paved the way for the Raft Foundation to develop a new concept and design and reasoning and analysis. In 1999, Sutradhar published some more acceptable rules for sorting the base of variable thickness for the Finite Element Method analysis.
OBJECTIVE OF THE PRESENT RESEARCH The main purposes of the exploration are as follows: -
The design is web floor beams on an elastic foundation with loads applied to the floor beam connections.
RESEARCH METHODOLOGY
LITERATURE REVIEW
Bearing Capacity of Foundation
Given the importance of Terzaghi's original solution to most subsequent work, it is considered useful to repeat the above basic information that does not resist its appearance in most publications.
Types of Foundation
There are many types of foundations for buildings, but here we will discuss pile and raft foundations in detail. However, the most important attention is the cost of these two types of foundations from this analysis. Its analysis will show the longevity of a foundation and how much pressure it can take.
A raft foundation usually covers the entire surface of the building, thereby distributing the total load over a larger area than the foundation foundation and reducing the bearing pressure to a minimum. The choice between a rafter and a base depends on the properties of the soil and the weight of the building. If the conceptual design of the foundations of the foundations reveals that the sum of the areas of the foundations required for installation on the structure exceeds 60% of the total area of the building; preference should be given to a rafter foundation that covers the entire area of the building.
Furthermore, the amount of differential settlement may be excessive for a footed foundation, where soil properties vary largely across the site, but in a raft foundation the effect of randomly distributed weak zones tends to level out. Therefore, the Jess settlement pattern is erratic and the differential settlement is also significantly reduced.
Bearing Capacity of Raft or Mat Foundation
For Floating on clay, the safety factor should not be less than 3 under dead load or maximum live load. However, under the most exciting conditions, the safety factor should be at least 1.75 to 2. Under most operating conditions, the factor of safety against bearing failure of rafts on sand is very large.
The allowable net bearing capacity of mats constructed over granular soil deposits can be adequately determined from standard penetration resistance figures. In general, shallow foundations are designed for a maximum settlement of 25 mm and a differential settlement of about 19 mm.
Structural Design of Raft or Mat Foundation
- Conventional Rigid Methodof Raft Foundation
- Approximate Flexible Method
- Analysis Procedure
- Types of Pile Foundation
- Meyerhof’s Method
Compare the soil pressure values determined in 2 with the net allowable soil pressure to determine if q ≤ 𝑞𝑛𝑒𝑡(𝑎𝑙𝑙). The contact pressure is taken as the average of the two end pressures of the strip. This average contact pressure of strip and column loads must be changed because they do not satisfy statics.
If the edge of the slab is in the zone of influence of a column, calculate the moment and shear force along the edge, assuming the raft is continuous. Different types of piles are used in construction, depending on the type of load to be carried, the subsoil and the location of the groundwater table. The portion of the load on the pile is resisted by shear resistance, compacted at the interface between pile and soil.
The remaining load is transferred through the base or tip of the pile. Where the pile width D is relatively small, the term 𝛾𝐷𝑁𝛾 can be omitted from the right-hand side of the previous equation without incurring serious error.
Column Load All Column load
Pile Cost Analysis Volume of pile = 𝜋𝐷 2
Pile Cap Cost Analysis
Affodil International University Total weight of distribution Bar Distribution beam above and below SR Details Dia.
Raft Foundation Allowable Bearing Capacity Check
Raft Foundation Punching Shear Check
Raft Foundation Bar Bending Schedule
Discussion Most Suitable for the Foundation
CONCLUSONS
