REINFORCED CONCRETE QUESTIONS AND ANSWERS

Abutment - answer-structure for anchoring the reinforcing tendons in the pretension over concrete member Anchor - answer-mechanical device for locking a stress tendons in position in delivering the prestressing force to the concrete either permanently in a post tension member or temporary during hardening of pretension concrete member. Also called anchorage Anchorage - answer-any of various means such as embedment length or bars, for developing tension or compression in the reinforcing bar on each side of a critical section in order to prevent bond failure or splitting Balance section - answer-a concrete section in which this the tension reinforcement theoretically reaches its specified yield strength of the concrete in compression pictures it's assumed ultimate stream Bar spacing - answer-the center to center spacing of parallel reinforcing bar, resulting clear distance between the bar being regula ted by bar diameter, maximum size of coarse aggregate, and thickness of the concrete section Beam an girder slab - answer-one way slab supporting by secondary beams which in turn are supported by primary beams or girder Bent bar - answer-longitudinal bar bent to an angle of 30 degrees or more with the axis of a concrete beam, perpendicular to and intersecting. Cracking. Could occur from the diagonal tension Bond - answer-the adhesion between two substances such as concrete and reinforcing bars Bond stress - answer-the adhesive force per unit area of contact between the rain forcing bar in the surrounding concrete developed at any section of a flexural a member Bonded posttensioning - answer-posttensioning in which the reinforcing tendons are bonded to the surrounding concrete by injecting grout into the annular spaces around the stands Bonding layer - answer-a thin layer of mortar spread on a moistened in prepared existing concrete surface prior to laying a new concrete slab Bottom bar - answer-any of the longitudinal bar serving as tension reinforcement in the section of a concrete beam or slab subject to a positive moment Butt splice - answer-a splice for transmitting pencil or compressive stresses from one longitudinal bar to another, made by butting their ends together and connecting them in a positive fashion Casting bed - answer-long horizontal slab on which a number of pre-tension concrete members may be prestressed, form in case simultaneously Column capital - answer-the head of a column support for a flat slab enlarged increase the plate area in shear Column strip - answer-panel strip occupying the adjacnt quarter panels on both sides of a column center line Composite column - answer-structural steel sections are only in case in concrete reinforced with both vertical and spiral reinforcement Compound column - answer-is structural steel column in case in concrete at least 2 1/2 inch for 64 mm thick reinforced with wire mesh Compression reinforcement - answer-reinforcement designed to absorb compressive stresses Compression splice - answer-a butt splice made by connecting a butted end of to enforcing bar with a mechanical fasteners such as a sleeve clamp Concentric tendon - answer-a tendons having a trjectory coincident with the centroidal axis of a prestressed concrete member. When tension the tendons produces a uniformly distributed compressive stress across the section that counteracts the tension stress from bending Continuous slab - answer-is subjected to lower bending moment than a serious of discrete simply supported slabs Continuous slab - answer-reinforced concrete slab extending as a structural unit of three or more supports in a given direction Cover - answer-the amount of concrete required to protect steel reinforcement from fire and corrosion, measured from surface to the reinforcement to the outer surface of the concrete section Cracked section - answer-concrete section design or analyzed on the assumption that concrete has no resistance to tensile stresses Cracking load - answer-the load that causes the tensile stresses in a concrete member to exceed the tensile strength of the concrete Critical section - answer-the section of a flexural concrete member at a point of maximum stress, a point of inflection or a point within the span where tension bars are no longer needed to resist stress Deep beam - answer-reinforced concrete beam having a depth to span ratio greater than 2: 5 for continuous span or 4:5 simple spans subject to nonlinear distribution of stress in lateral back clean Deform bar - answer-reinforcing bar hot rolled with surface deformations to develop greater bond with concrete Depressed tendon - answer-pretensioning tendon thay approximate the curve of a drapef tendon with straight line segments, use in the pretensioning process since the prestressing force does not allow for draing the tendon Diagonal tension - answer-principal tensile stresses acting at an angle to the longitudinal axis of a beam Distribution rib - answer-rib formed perpendicular to the joist of ribbed slab to distribute possible load concentrations over a larger area, one required for span between 2o-30 ftor 6 to 9 meters in 2/4 bands / 30 ft Dome - answer-square metal or fiberglass pan used in forming the rib of waffle slab available in standard 19 and 30 inch or 483 - 762 mm widths and variety of depth Double tee - answer-precast,prestressed concrete slab having two stamps in a broad cross section resembling the capital letter tt Draped tendon - answer-post tensioning tendon havin a parabolic trajectory that mirrors the moment diagram of a uniformly distributed gravity load. When tension, the tendon produces a variable eccentricity that respond to the variation in applied bending moment along the length of the member Drop panel - answer-the portion of the flat slab thickened around the column or column capital to increase its resistance to shear Eccentric tendon - answer-tendon having a trajectory not coincident with the cebtroidal axis of prestressed concrete member. When tension, the tendon producers in a eccentric prestressing force that reduces the compressive stress across the section to that produced by behind alone Effective area of concrete - answer-the area of a concrete section between the compression face in the centroid of the tension reinforcement Effective area of reinforcement - answer-the product of the right cross sectional area of reinforcement in the cosine of the angle between the direction in the direction for which its effectiveness is considered Effective depth - answer-the depth of concrete section measured from compression face to the centroid of the tension reinforcement Effective prestressed - answer-final prestress in a prestressed concrete member, including the effect of the weight of the member but excluding the effect of any superimpose load Embedment length - answer-the length of embedded reinforcement provided beyond a critical section for anchorage Exterior panel - answer-panel of a flat slab having at least one inch that does not a joint another panel Ferrocement - answer-constructed of cement and mortar over a wire mesh that has been pre shape over a mold Fiber reinforced concrete - answer-concrete reinforced with this purse, randomly oriented fiber of glass or plastic Final prestress - answer-the internal stress that exist in the prestressed concrete member after all losses in pre stress have occurred Flat plate - answer-are suitable for short to medium spend with relatively light live loads. Since there are no column capitals or drop panels, shear governs the thickness of a flat plate Flat plate - answer-concrete slab of uniform thickness reiforced in two or more direction in the board that directly by columns without beams or girders Flat slab - answer-flat plate thickened at its column to support to increase its shear strength and moment resisting capacity, suitable for heavy loaded span Gfrc - answer-abbreviation for glass fiber reinforced concrete Harped tendon - answer-one of a series of depressed tendons having varying slopes Hollow core slab - answer-precast, prestressed concrete plank internally cord to reduce the wait. Suitable for medium to long span and uniformly distributed floor and roof loads Hook - answer-a bend or curve given to the end of a tension bar to develop an equivalent embedment length, used where there is insufficient room to develop an adequate embedment length Initial prestress - answer-the tensile force in the rain forcing tendons transferred to a concrete members at the time of stressing Interior panel - answer-any panel of a flat slab by joining other panels along all four edges Inverse tee - answer-precast ,prestressed ledger been having a cross section resembling the capital letter t Jack - answer-hydraulic device for stretching in stressing tendons in the prestressing over concrete members Jacking force - answer-tensile force exerted temporally by a jack in the pre stressing over concrete member Joist band - answer-broad shallow supporting beam for a ribbed slabs that is economical to form since it depth is the same as t joist L beam - answer-precast,prestressed ledger being having a cross section resembling the capital letter l Lap splice - answer-a splice for transferring tensile or compressive stresses from one longitudinal bar to another, made by lapping there and for a length specified in a bar diameter Lateral reinforcement - answer-spiraled enforcement or lateral ties place in a concrete column to laterally restrain the vertical reinforcement and prevent buckling Ledger beam - answer-reinforced concrete beam having projecting ledges for receiving the end of joist slab Load balancing - answer-the concept of prestressing concrete member with that drape tendons, theoretically resulting in a state of zero deflection under a given loading condition Longitudinal reinforcement - answer-reinforcement essentially parallel to the horizontal surface of a slab or to the long axis of the concrete beam or column Loss of prestress - answer-reduction in initial prestress resulting from the combined effect of creep . Shrinkage or elastic shortening of the concrete, relaxation of the rainforest in steel, friction losses resulting from the curvature of repentance, and slipping at the anchorage Middle strip - answer-pannel strip, one half panel width and symmetrical about the panel center line Mushroom constru