An-Najah Nationa Unuversity Faculty Of Engineering Civil Engineering Department Nablus-Palestine Foundation Design of Multy story building Suprevisors: Dr.Sami Hijawwi Perpared By: Asmaa Abed-Al Hadi Mardawi Rasha Estewi Maysoon Sbeeh

Chapter One General definition of the project Our project is to foundation design of a residential building which consists of seven stories.

Chapter two talks about literature review of Foundations It’s function is to transfer the load of the structure to the soil on which it’s resting. A properly designed foundation transfers the load throughout the soil without overstressing the soil. Thus, geotechnical and structural engineers who design foundations must evaluate the bearing capacity of the soil.

Depending on the structure and soil Characteristics, type of foundation is used: 1-Raft or mat foundation Mat foundation is a type of shallow foundation which is used if the soil layer near the ground surface has alow bearing capacity. the column loads are so large that the sum of the areas of the isolated footings required to support the structure exceed 50%of the total area of the building.

2-Pile foundation Piles are used to transmit the load to underlying bedrock or a stronger soil layer. Piles are used when the soil too weak, when subjected to horizontal forces… etc, the cost is more than shallow foundations.

Settlement of foundation The settlement of a structural foundation consists of three parts: 1- Immediate settlement: takes place during application of the loading as a result of elastic deformation of the soil(no change in water content). 2- Consolidation settlement takes place as a result of volume reduction of the soil caused by extrusion of some of the pore water from the soil. 3- Creep or secondary settlement occurs over a very long period of years after completing the extrusion of excess pore water. Figure below Settlement stages with time.

Chapter 3:Summary of laboratory test results Natural moisture content (N.M.C): ranges between 8% %. 2- Liquid limit (L.L): ranges between % %. 3- Plasticity index (P.I): ranges between 10.5% - 22%. 4- Specific gravity = Allowable bearing capacity = 2.1 Kg/cm 2.

Chapter 4:Descriptions of loads building and its structure The structural system of this building is typical one, consisting of slab, beams, and columns. The slabs are one-way in all floors. Descriptions of loads on the footing Dead loads Live loads

Chapter 5:Loads analysis Ultimate load ton Service load ton Dimensions m Column No * * * * * * * * * * *1.211

Ultimate load ton Service load ton Dimensions m Column No * * * * * * * * * *0.821

Chapter 6 Is the Basic part of this project; it handles with the analysis, design and settlement calculations of mat, and pile foundations.

3-D Mat Foundation

Determine the depth To determine the depth of the mat we should take the critical loads and positions. The depth of mat determined by the critical check which is punching shear check. We found it =120 cm.

Settlement of mat foundation from 2.4mm to maximum 33.5mm

Design of pile foundation 1-Estimating pile capacity The ultimate carrying capacity is equal to the sum of the ultimate resistance of the base of the pile and the ultimate skin friction over the embedded shaft length of the pile, this expressed by : Q u = Q S + Q P

2-Determination of the point bearing capacity For piles in saturated clay in undrained cohesion as our case, the point bearing capacity may be estimated as : Q P = 9 Cu Ap

3-Determination of skin resistance The formula of skin resistance of the pile can be expressed as: Q S = ∑ { α * P* ∆ L*cu }

This table presents the proposed dimensions of piles and there capacities in (KN). 15m 12 mDiameter/length 236 KN274 KN KN382 KN KN 1 We choose Pile diameter 1m and the length was 15 m

Cap dimensions The minimum distance between two terraced piles is 3D. Pile caps should extend at least 150 mm beyond the outside face of exterior piles. The minimum thickness of pile cap above pile heads is 300 mm.

The number of piles needed and cap dimensions are summarized in the table below: Pile Size (L,D)No. of piles Cap Dimensions (m) Column No. 15*1)) 4 4.4* *1)) 9 7.4* *1)) * *1)) * *1)) 6 7.4* *1)) 4 4.4* *1)) 77.4* *1)) 810.4* *1)) 810.4* *1)) 67.4* *1)) 77.4*5.511

Pile Size (L,D)No.of piles Cap Dimensions (m) Column No. (15*1) *7.412 (15*1)7 7.4*5.513 (15*1)5 5.5*5.514 (15*1)7 7.4*5.515 (15*1)7 7.4*5.516 (15*1)4 7.4*4.417 (15*1) 33.5*5.518 (15*1) 97.4*7.419 (15*1) 810.4*4.420 (15*1) 94.4*4.421

Reinforcement details of piles The structural design for all piles is : Pile diameter= 100cm. Pile gross area = (π/4)(100 2 )= 7850 cm². As min = 0.005Ag = 0.005*7850 = 39.25cm² Use 12Φ20 mm.

Reinforcement details of caps * Punching shear check: ФVc=Ф*1.06*√ fc*d*bo (kg,cm) * Wide beam check: ФVc=Ф*0.93*√ fc*d*b (kg,cm) Ast =ρ * B*d

Settlement of piles Elastic settlement for single pile Se = Se(1) + Se(2) + Se(3) Se1: Elastic settlement of pile. Se2: Settlement of pile caused by the load at the pile tip. Se3: Settlement of pile caused by the load transmitted along the pile shaft.

Elastic settlement of group of piles: Se = S * √(Bg / D) Se (rigid) = 0.93 * S e(elastic) The following table presents the elastic settlement of group of piles Se(rigid) (mm) Se(elastic) (mm) Diameter(m m) Length(m)

Consolidation settlement of piles This table summarized the results of calculation of consolidation settlement of piles: Consolidation settlemen ts of piles(mm) Cap dime nsion Service load (ton) Column No * * * * * * * * * * * * * *

Chapter 6 This Chapter aims to do some comparison,quantities calculations, discusses the results of the project, and it gives recommendations of what are the proper and most economical type of foundation for this building.

As a result of the previous analysis of the quantities of concrete and steel needed for the different types of foundation,, we recommend using mat footing instead of the pile footing. The following table summarizes the comparison : Mat footingPile footingComparison OK settlement Volume of concrete(m³) 0.85 ton/m8.89tonWeight of steel