RCD Assignment 1

REINFORCED CONCRETE DESIGN

1. Design Design a recta rectangul ngular ar beam beam reinforced for tension only to carry a dead load moment of 150 KN-m and a live load of 140 KN-m. fc’= 20. !"a# fy = 414 !"a $se %5 mm steel covering. 2. & reinfo reinforc rced ed recta rectangul ngular ar beam beam 'as a (idt' of )50 mm 'aving a sim*le s*an of %m. +t carries a dead load moment ,including its o(n (eig't of 100 KN-m a live load moment of 140 KN-m and a moment due to t'e e/ect of eart'uae of 11 KN-m. +f fc’ = 20. !"a (it' a steel yield strengt' of 414 !"a. a Determ Determine ine t'e design design moment. b Determ Determine ine t'e e/ecti e/ective ve de*t' of t'e beam. c 3o( 3o( many many 25 mm

bars bars

ASSIGNMENT No. 1

com*ression reinforcement if reuired (ill be *laced at a de*t' of %0 mm. if and design t'e steel reinforcement if t'e beam is to su**ort a bending moment of %50 KNm. 5. & recta rectangul ngular ar rein reinfor forced ced concrete beam 'as a (idt' of )00 mm and an e/ective de*t' of 450 mm. +t is reinforced reinforced for tension at t'e bottom (it' a total steel area of 6%2.5

fc’ = 24.2 !"a# fy = )45.% !"a# 7s = 200 000 !"a. a 7valua 7valuate te t'e curvat curvature ure

are needed for t'e reinforcement. ). & reinfo reinforc rced ed concr concrete ete beam beam 'as a (idt' of )00 mm and an e/ective de*t' to t'e tension reinforcement reinforcement of %00 mm. om*ression reinforcement of %00 mm. om*ression reinforcement reinforcement if reuired (ill be *laced at a de*t' of %0 mm. +f fc’ = )00 mm and fy = 410 !"a design t'e longitudinal reinforcement reinforcement if t'e beam is to su**ort a bending moment of %50 KN-m. 4. & reinfo reinforc rced ed concr concrete ete beam beam 'as a (idt' )00 mm and an e/ective de*t' to t'e tension reinforcement reinforcement of %1 mm. CENG 115

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due to t'e moment ('ic' *roduces initial yielding of t'e tension steel in radians *er meter. b 7valua 7valuate te t'e curvat curvature ure due to nominal 8e9ural strengt' !n of t'e cross section in radians *er meter. c Determ Determine ine t'e magnit magnitude ude of t'e cross sections curvature ductility ratio. %. &n under under rein reinfor forced ced beam beam 'as a (idt' of )00 mm and an e/ective de*t' of 425 mm is reinforced (it' a total steel area of 5

. +ts neutral a9is is

REINFORCED CONCRETE DESIGN

located at 102.5 mm belo( t'e to* of t'e beam. fc’ = 24.6 !"a# fy = 414. !"a# 7s = 200 000 !"a. a om*ute t'e magnitude of t'e moment t'at *roduces initial failure of t'e cross section ,:ension ;teel ;trained to



b om*ute t'e associated curvature

.

c om*ute t'e stress fc at t'e to* surface of t'e beam. . $sing $;D met'od design a sim*ly su**orted reinforced concrete beam 0.20 m (ide and 4.50 m long carrying only a (all load of .2 KNm including its o(n (eig't. Kee* t'e steel ratio (it'in 1 < and use 1% mm reinforcing bars. $se fy = 41). !"a fc’ = 2.% !"a and a minimum concrete cover of %).5 mm. +ndicate t'e de*t' and number of reinforcing bars on t'e gure>

ASSIGNMENT No. 1 Wu = 11. 578 KN/m

4.5 m

. ;ection 5.10.).2 and 5.10.).) of  t'e 1662 National ode of t'e "'ili**ines states as follo(s> ?alanced strain conditions e9ist at a cross section ('en tension reinforcement reac'es t'e strain corres*onding to its s*ecied yield strengt' fy @ust as concrete in com*ression reac'es its ultimate strain of 0.00). for 8e9ural members sub@ect to combined 8e9ural and com*ressive a9ial load ('en t'e design a9ial load strengt'

is less t'an t'e

smaller of 0.10 fc’ &g or

t'e

ratio of reinforcement *rovided s'all not e9ceed 0.5 of t'e ratio

t'at (ould

*roduced balanced strain conditions for t'e section under t'e 8e9ure (it'out a9ial load. Aor members (it' com*ression

200

reinforcement t'e *ortion of        d

       5  .        3        6

CENG 115

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eualiBed by com*ression reinforcement need not be reduced by t'e 0.5 factor. & singly-reinforced concrete beam 'as a (idt' of )00 mm and an e/ective de*t' of 400 mm. oncrete strengt' is 24 !"a and steel yield strengt' is )40 !"a.

REINFORCED CONCRETE DESIGN

Determine t'e ma9imum allo(able steel area n accordance (it' t'e 1662 N;" strengt' design met'od. 6. & sim*ly reinforced concrete beam 'as a (idt' of 250 mm and an e/ective de*t' of 500 mm concrete strengt' is 2 !"a and fy = 20 !"a. Determine> a ?alanced reinforced ratio in *ercent. b !a9imum allo(able steel area accordance (it' 1662 N;". c Number of 25 mm bar to be used. 10.& reinforced concrete beam 'as t'e follo(ing *ro*erties> b = )20 mm# d = %40 mm# fc# = 25 !"a# fy = 400 !"a and 7s = 200 000 !"a. +f t'e beam is to be designed for a balanced condition nd t'e reuired area of steel reinforcement in

. 3int> :'e

balanced steel area = 0.5 &sb.

ASSIGNMENT No. 1

Determine t'e reuired number of 20 mm C tensile reinforcement over eac' su**orts and at eac' of t'e *oints of ma9imum *ositive moments bet(een t'e su**orts. &lso determine t'e ma9imum s*acing at t'e faces of t'e su**orts of 10 mm C stirru*s. $se fc = 21 !"a fy = 25 !"a.

12.Arom t'e given cross section of  a rectangular beam reinforced for tension only. Diameter of stirru*s = 10 mm. lear s*acing bet(een layers of bars = 25 mm. lear cover of stirru*s = 40 mm Diameter of 4 lo(er bars = 25 mm. Diameter of 4 u**er bars = 2 mm. Determine t'e follo(ing> a. 7/ective tension area of  concrete b. alue of crac inde9 c. &llo(able values of crac inde9 for interior e9*osure and e9terior e9*osure. •

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11.Aor t'e continuous beam s'o(n by moment distribution calculate t'e magnitudes of t'e ma9imum negative moments over t'e su**orts# dra( t'e s'ear and moment diagrams s'o(ing t'e locations of t'e *oints of in8ection and t'e *oint of ma9imum *ositive moments and t'e total vertical reactions at all su**orts. Neglect t'e dead (eig't of t'e beam. $sing an e/ective d = 5%0 mm. CENG 115

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REINFORCED CONCRETE DESIGN

1).Eiven t'e cross section of t'e beam 'aving a dimension of  20 9 %00 mm and is reinforced (it'  F 20 mm C bars arranged as s'o(n. Determine t'e follo(ing> a. lear 'oriBontal s*acing bet(een bars b. Narro(est dimension of   'oriBontal forms c. !a9imum siBe of coarse aggregates

14.& reinforced concrete beam 'aving a (idt' of 20 mm and a total de*t' of %00 mm is reinforced for tension at t'e bottom (it' % F )% mm C bars *laced on t(o layers as s'o(n. Determine t'e follo(ing> a. 7/ective de*t' of beam b. lear 'oriBontal s*acing bet(een bars c. !a9imum siBe of coarse aggregates

CENG 115

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ASSIGNMENT No. 1

15.& reinforced concrete beam 'as a (idt' of )00 mm and an e/ective de*t' of %00 mm fc = )5 !"a fy = 400 !"a. Determine t'e follo(ing> a. alue of t'e G factor b. alue of balanced steel ratio c. Number of 2 mm C 1%.:'e reinforced concrete beam 'as a (idt' of 250 mm and a e/ective de*t' of 500 mm. t'e com*ressive strengt' of   concrete is 2 !"a and t'e yield strengt' of t'e steel reinforcement is 414 !"a. 7s = 200 000 !"a. Determine t'e follo(ing> a. !a9imum steel area reuired b. Number of 25 mm C bars c. $sing ma9imum number of  25 mm C bars com*ute t'e nominal moment ca*acity of  beam. 1.:'e cross section of a rectangular reinforced beam 'as a (idt' of 250 mm and d = )%0 mm and reinforced for tension (it' &s = %00 mm 2 fc = 40 !"a fy = 400 !"a and 7s = 200 000 !"a. Determine t'e follo(ing>

REINFORCED CONCRETE DESIGN

ASSIGNMENT No. 1

a. Hocation of neutral a9is belo( t'e com*ression surface b. ;train reuired to yield t'e steel c. ondition of t'e beam 1.& reinforced concrete 'aving a (idt' of 250 mm and an e/ective de*t' of 500 mm 'as coeIcient of resistance of 5.)2. +f fc = )5 !"a and fy = 25. !"a. Determine t'e follo(ing> a. !a9imum ultimate moment ca*acity of beam b. ;teel ratio of t'e beam c. ;teel area reuired by t'e beam 16.& reinforced concrete beam 'as a (idt' of )50 mm and d = %60 mm. if fc = 20. !"a and fy = 414 !"a. Determine t'e follo(ing> a. !a9imum steel ratio b. oeIcient of resistane for a steel ratio F eual to J *ma9 c. $ltimate factored moment ca*city 20.& symmetrical cross-section of a reinforced concrete s'o(n 'as a value of fc = 24.1) !"a and fy = 42. !"a 7s = 200 000 !"a. Determine t'e follo(ing> a. Hocation of neutral a9is from t'e to* of t'e beam for a balanced condition b. ?alanced steel area &sb c. !a9imum area *ermitted by t'e code.

CENG 115

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21.& rectangular reinforced concrete beam 'as b = )00 mm and total de*t' 40 mm. it is reinforced (it' a total steel area in tension eual to 220 mm 2. 7/ective de*t' of t'e beam is 400 mm. fc = 20.% !"a fy = )44. !"a. Determine t'e follo(ing> a. urvature of t'e beam due to nominal 8e9ural strengt' of t'e beam in radians *er meter b. !a9imum value of factored moment !u t'at t'e cross section can su**ort c. oeIcient of resistance of  beam.