Tiêu đề PSAD 42 - Pile Footings.pdf ✅

Computing the two-way shear, Vu = 8Ru = 8(477.778) = 3822.222 kN b0 = 4(400 + 450) = 3400 mm τu = 3822.222(1000) 3400(450) = 2.498 MPa τn = 2.498 0.75 = 3. 331 MPa For the design moment, Mu = 3Ru (1 − bcolumn 2 ) = 3(477.778) (1 − 0.4 2 ) = 1146. 667 kNm
Problem 2. A reinforced concrete rectangular footing rests on five piles with diameter of 300 mm, and is subjected to the following loads: Axial Loads: PDL = 600 kN, PLL = 450 kN Moment about y-axis: MDL = 112 kNm, MLL = 60 kNm Moment about x-axis: MDL = 150 kNm, MLL = 120 kNm The footing is 700 mm thick and supports a column 500 mm by 500 mm. Concrete cover to steel reinforcement is 75 mm. fc ′ = 24 MPa and fy = 420 MPa. Assume 25-mm bars are to be used as flexural reinforcements. 1. What is the maximum pile reaction in kN? 2. What is the nominal wide beam shear stress in MPa? 3. What is the nominal punching shear stress at the column? 4. What is the nominal punching shear stress at the most stressed pile? Solution: Ru1 = Pu n − Muyx ∑ x 2 − Muxy ∑ y 2 Ru2 = Pu n + Muyx ∑ x 2 − Muxy ∑ y 2 Ru3 = Pu n − Muyx ∑ x 2 + Muxy ∑ y 2 Ru4 = Pu n + Muyx ∑ x 2 + Muxy ∑ y 2 Ru5 = Pu n