A precast beam is steam-cured for 24 hours and then prestressed. The level of prestressis 7 MPa and the compressive strength of concrete is 25 MPa. The beam is then exposedto 70% RH. Determine the total strain at the end of the first year. Given the density ofconcrete is 2320 kg/m3. [Ans: 1.34 × 10-4]

A precast beam is steam-cured for 24 hours and then prestressed. The level of prestressis 7 MPa and the compressive strength of concrete is 25 MPa. The beam is then exposedto 70% RH. Determine the total strain at the end of the first year. Given the density ofconcrete is 2320 kg/m3. [Ans: 1.34 × 10-4]

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

Please give me the correct solution and answer of this problem in principle of reinforced/prestressed concrete
Concrete is required for a column that will be moderately exposed to freezing and thawing. The cross section of the column is 300 × 300 mm. The smallest spacing between reinforcing steel is 30 mm. The specified compressive strength of concrete at 28 days is 40 MPa with a slump of 80 to 100 mm. The properties of materials are as follows: ❖ Cement used is type I Portland cement with a specific gravity of 3.15. ◆ The available coarse aggregate has a maximum size of 23 mm, a dry-rodded unit weight of 1800 kg/m3, a bulk specific gravity (SSD) of 2.7, absorption capacity of 0.55%, and moisture content (SSD) of 0.25%. The fine aggregate has a bulk specific gravity (SSD) of 2.75, absorption capacity of 1.4%, a moisture content (SSD) of 2.5%, and a fineness modulus of 2.70. The aggregates conform to the ASTM C33-84 requirements for grading.
The width of the expansion joint is 20mm in a cement concrete pavement. The laying temperature is 20 °C and the maximum slab temperature in summer is 60 °C. The coefficient of thermal expansion of concrete is 10 x 10-6 mm/ mm / °C and the joint filler compresses upto 50% of the thickness. The spacing between expansion joints should be
I want the solution in less than 15 minutes
The concrete in the core of a spiral column is sub- jected to a uniform confining stress o, of 680 psi. What will the compressive strength o be? The un- confined uniaxial compressive strength is 5000 psi.
Concrete is required for a column that will be Severe exposed to freezing and thawing. The cross section of the column is 300 × 300 mm. The smallest spacing between reinforcing steel is 30 mm. The Required Average Compressive Strength of concrete at 28 days is 35 MPa with a slump of 80 to 100 mm. The properties of materials are as follows: ❖ Cement used is type I Portland cement with a specific gravity of 3.15. ◆ The available coarse aggregate has a maximum size of 23 mm, a dry-rodded unit weight of 1800 kg/m3, a bulk specific gravity (SSD) of 2.7, absorption capacity of 0.55%, and moisture content (SSD) of 0.25%. The fine aggregate has a bulk specific gravity (SSD) of 2.75, absorption capacity of 1.4%, a moisture content (SSD) of 2.5%, and a fineness modulus of 2.70. The aggregates conform to the ASTM C33-84 requirements for grading.
Concrete is required for a column that will be Severe Exposure to freezing and thawing. The cross section of the column is 300 × 300 mm. The smallest spacing between reinforcing steel is 40 mm. The specified compressive strength of concrete at 28 days is 40 MPa with a slump of 25 to 50 mm. The properties of materials are as follows: (a) Cement used is type I Portland cement with a specific gravity of 3.10. (b) The available coarse aggregate has a maximum size of 23 mm, a dry-rodded unit weight of 1800 kg/m3, a bulk specific gravity (SSD) of 2.68, absorption capacity of 0.65%, and moisture content (SSD) of 0.27%. (c) The fine aggregate has a bulk specific gravity (SSD) of 2.75, absorption capacity of 1.5%, a moisture content (SSD) of 2.5%, and a fineness modulus of 2.7,The aggregates conform to the ASTM C33-84 requirements for grading.
Problem 2: If f = 3 ksi what is the modulus of elasticity Ec and the maximum tensile stress fr that the concrete can carry before cracking (use ACI recommended equations). Assume a unit weight of the plain concrete is: a. Wc = 90- b. w lb lb 118- ft39 ft3) C. W = 160- Problem 3: Wight 3-6 Rugblom 4: Wight ? 7 lb ft3
Estimate the tensile strength required to prevent cracking in a concretelike material that is cast into a bar, 1.25 m long, and is fully restrained ateach end against axial movement. The concrete is initially cast and curedat a temperature of 40°C and subsequently cools to a temperature of –20°C.Assume that the modulus of elasticity is 35 GPa and the thermal coefficient is9 X 10-6m/m/°C.
e. Before loading, the concrete shrinks &z-conc = 0.05 (0.5%). This is less than if it were not restrained by “temperature steel", so the downdrag preloads the steel ơ2-0 = 3,000 psi. When the P = 200K is applied, estimate the final stress in the steel. %3D %3D
Concrete is required for walls of a building that will be Severe Exposed to freezing and thawing. The cross section of a wall is 300 x 1500 mm. The smallest spacing between reinforcing steel is 50 mm. The Required Average Compressive Strength of concrete at 28 days is 40 MPa and a slump of 55 mm. Portland cement type I is used with specific gravity of 3.12, maximum size of aggregate 27 mm and fineness modulus of fine aggregate is 2.4, absorption capacity and moisture content of fine aggregate are of 0.92%, and 1.95% respectively. The dry-rodded unit weight of coarse aggregate is 1820 kg/m³, absorption capacity and moisture content of coarse aggregate are of 0.75%, and 1.85% respectively. Both aggregates have a bulk specific gravity (SSD) of (2.45). The aggregates conform to the ASTM C33-84 requirements for grading. Estimate the quantity of (cement, fine aggregate, coarse aggregate and water) for 1m³ concrete.
Cracking Analysis of Reinforced Concrete ANSWER A. TO G. COMPLETE SOLUTIONS -positive bending moment = +200KNm -draw transformation of areas -draw strain and stress diagram