BEHAVIOUR OF WIDE REINFORCED CONCRETE BEAMS WITH DIFFERENT SHEAR STEEL PLATES SPACING

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1 ; Vol. 20, No.05, September 2016 ISSN BEHAVIOUR OF WIDE REINFORCED CONCRETE BEAMS WITH DIFFERENT SHEAR STEEL PLATES SPACING Dr. Amer M. Ibrahim 1, Dr. Mohammed J. Hamood 2, *Ahmed Abdllah Mansor 3 1) Pr., Civil Engineering Department, Diala Universit, Baqba, Iraq. 2) Assist Pr., Civil Engineering Department, Universit Technolog, Baghdad, Iraq. 3) Lectrer, Civil Engineering Department, Diala Universit, Baqba, Iraq. Abstract: This paper presents an experimental investigation on the behavior wide reinforced concrete beams with different shear steel plate spacing. For reinforced concrete wide beams with the dimensions 215x560x1800mm are investigated. The variables stdied in this work is sing the 10mm stirrps with 125mm spacing and 3mm thickness steel plate with spacing 125, 166 and 250mm instead reinforcing stirrps. Shear steel plates is a good alternative for stirrps and gives identical reslts in ield and ltimate loads and increase the dctilit b 55% and redced the strain in exterior and interior legs b 17% and 46% respectivel compared with stirrps also redced the total weight wide beams b 2.7%. B increasing the spacing shear steel plate b 33% and 100%, the reslts showed that the ield load redced to 5% and 12% respectivel, bt the deflection was increased with 2% and 16% respectivel(at ield). The strain in interior legs is more than the strain in exterior leg (having spacing 125, 166 and 250mm) b 31%, 70% and 1% respectivel. ACI (1) and EC 2 (2) codes are given a predicted deflection less than the experimental deflection b 19% and 21% on average respectivel. Kewords: Reinforced Concrete; Wide Beam; Stirrps, Shear Steel Plate,. تصرف العتبات الخرسانية المسلحة العريضة بأختالف المسافات بين صفائح حديد القص الخالصة: يتضمن هذا البحث دراسة عملية لتصرف العتبات الخرسانية العريضة بأختالف المسافات بين صفائح حديد القص. اشتملت الدراسة على صب اربع عتبات خرسانية مسلحة عريضة بابعاد ) 560x215x1800 (ملم. لقد تم دراسة متغيرات عديدة منها استخدام اطواق بقطر 10 ملم بمسافات 125 ملم واستخدام صفائح من الحديد بسمك 3 ملم وبمسافات و 250 ملم بدال من حديد القص. ان استخدام الصفائح كبديل عن االطواق اعطى تطابق في نتائج حمل الخضوع والفشل وزاد من المطيلية بنسبة %55 وقل ت فيه االنفعاالت في الساق الخارجية والداخلية بنسبة %17 و %46 على التوالي مقارنة مع االطواق اضافة الى تقليله الوزن الكلي للعتبات العريضة بنسبة %2.7. ان زيادة المسافات بين صفائح حديد القص بنسبة %33 و %100 قلل من حمل الخضوع بنسبة %5 و %12 على التوالي ولكن زاد من الهطول بنسبة %2 و %16 على التوالي )في مرحلة الخضوع(. ان االنفعال في الساق الداخلية اكبر من االنفعال في الساق الخارجية )للمسافات و 250 ملم( بنسبة %31 %70 و %1 على التوالي. الكود االمريكي (1) ACI واالوربي (2) 2 EC اعطى نتائج للهطول اقل من النتائج العملية بنسبة %19 و %21 على التوالي. 1. Introdction The se wide concrete beams in strctral framing sstems has improved in latest ears. This is alteration responds to the necessit for inexpensive kes which redce *Corresponding Athor aamansor2003@ahoo.com 120

2 strctral high and bilding complexities. For example, engineers new high-rise bildings are freqentl tasked with conveing colmn loads from the tower portion above reqired colmn-free spaces in the pedestal or parking areas below. Wide beams ma provide sitable cross-sectional areas to do the reqired abilit in a shallower depth than a sstem slenderer beams at a parallel spacing in the plan, as well as reinforced concrete wide beam-colmn connections, it has high efficienc to resist earthqake loads. Adam S. Lbell, et. al (2006) (3), carried ot an experimental std to investigate the shear behavior the wide beams and thick slabs as well as the inflence member width. In their std the tested five specimens normal strength concrete with a nominal thickness 470 mm and varied in width from 250 to 3005 mm. Their std demonstrated that the failre shear stresses narrow beams, wide beams, and slabs are all ver similar. Adam S. Lbell, et. al (2009) (4), investigated the inflence the shear reinforcement spacing on the one-wa shear capacit wide reinforced concrete members. A series 13 normal strength concrete specimens were designed and tested. Shear reinforcement spacing was a primar test variable. The specimens contained shear reinforcement ratios close to (ACI ) minimm reqirements. The std conclded that the effectiveness the shear reinforcement decreases as the spacing web reinforcement legs across the width a member increases, the se few shear reinforcement legs, even when widel spaced p to a distance approximatel 2d, has been shown to decrease the brittleness the failre mode compared with a geometricall similar member withot web reinforcement. To ensre that the shear capacit all members with shear reinforcement are adeqate when designed according to ACI , the std recommended that the transverse spacing web reinforcement shold be limited to the lesser both the effective member depth and 600 mm. Mohamed M. Hanaf, (2012) (6), investigated the contribtion web shear reinforcement to shear strength shallow wide beams and the test reslts clearl demonstrate the significance the web reinforcement in improving the shear capacit and the dctilit the shallow wide beams which is consistent with the recognized international codes and standards provisions. In this paper, an experimental and theoretical analsis to predict the deflection, strain, cracks patterns based on the for fll scales wide reinforced concrete beam tested. 2. Research significance The std focses on behavior wide reinforced concrete beams sing shear steel plate with different spacing. This new technic treats the crowded stirrps in wide concrete beam becase the shear component provided b concrete is ver small compared with high depth concrete beams. Also this std is an attempt to std the effect se the steel plate with different spacing on the deflection, strain and crack pattern wide beams. 121

3 3. Details experimental test 3.1 Otline program The experimental program consisted testing for beams with nominal compressive strength f c =33MPa (Self Compacting Concrete SCC) in a for-point loading arrangement. All beams were constrcted in the laborator the Engineering College Diala Universit. All beams were 560 mm wide, 215 mm deep, 1800mm long and were tested at a shear span 600 mm (the width spports is 600mm). This gives a shear span-depth ratio (a/d) eqal to The longitdinal steel reinforcement ratio was ρ=2.1%, with 16mm diameter and sing 10mm diameter in compression reinforcement with 415MPa and 397MPa ield strength respectivel. All the specimens were reinforced with identical longitdinal steel bars. For wide beams are tested, one as reference with shear steel reinforcing (stirrps) (WBS), and three with shear steel plate have eqivalent cross sectional area for stirrps at mid legs height and having 135mm circlar opening and 3mm thickness. The spacing between stirrps is 125 mm and it was (125, 166 and 250mm) for shear steel plate (WBP3-1, WBP3-2 and WBP3-3) and the ield strength shear steel plate is 210MPa. Tpical concrete dimensions and reinforcement details the tested specimens are illstrated in Fig. 1 and cross sections in Fig 2 and 3. The placement longitdinal reinforcement, shear steel plate and mold specimen shown in Fig Tested method and measrement All beams were tested nder simpl spported condition over a span 1.8m with their tension faces ppermost as shown in Fig.1. For all beams, the first crack load, deflection nder loading point, steel plate strains and ield, ltimate load were measred. 4. Test reslts The strength characteristics all specimens(f'c, ield, ltimate load and deflection at ield and ltimate loads also the vales dctilit) are tablated in Table (1). Accenting was taken in marking the load at which the first crack formed. The experimental vales the cracking loads were obtained from load-deflection diagrams. Fig. 1 Loading details 122

4 Fig. 2 Section A-A for stirrps(wbs beam) Fig. 3 Section A-A for plates(wbp3-1 beam) Fig. 4 Peparation the mold specimen and placing the reiforcement 4. 1 Load deflection relationships Table (1) shows the vales deflection at ield and ltimate load that were obtained from load-deflection diagrams. It can be seen from Table (1) that the deflection at ield was increased in specimens that sed the shear steel plate with 24%, 21% and 5% for specimens WBP3-1, WBP3-2 and WBP3-3 respectivel. This increasing deflection was clear in ltimate load for the specimens WBP3-1, WBP3-2 and WBP3-3 when it compared with the WBS specimen b 92%, 22% and 20% respectivel. Also the dctilit index was increased for the specimen WBP3-1 and WBP3-3 b 55% and 15% compared with WBS. B increasing the spacing shears steel plate b 33% and 100%, it can be seen from Table (1) that the deflection at ield was increased with 2.2% and 16% respectivel this is obvios, de to increasing shear steel plates spacing. This increasing deflection was clear in ltimate load for the specimens WBP3-2 and WBP3-3 when comparing with the WBP3-1 specimen b 37% as a reslt increasing spacing shear steel plate. 123

5 LOAD(kN) Jornal Engineering and Sstainable Development Vol. 20, No. 05, September (ISSN ) Table (1) Comparison between the strength characteristics specimens Beam Specimens f c (MPa) P P Dctilit Weight (ton) Weight WBS WBP % % % WBP % % % WBP % % % Fig (5) shows the load- mid span deflection crves for the specimens. It can be seen that the deflection at ield were close between all specimens, bt the behavior is different at ltimate load corresponding to decrease ltimate load. Also it can be seen that the dctilit WBP3-1 is more than 55% compared with WBS specimen WBS WBP3-1 WBP3-2 WBP DISPLACEMENT(mm) Fig. (5) Load-mid span deflection crves tested specimens 4.2 Comparison the deflection predicted b ACI (1) and EC 2 (2) codes Table (2) shows the vales deflection at service load (assme 60% from the ltimate load) obtained from load-deflection diagrams, also the analtical reslts all specimens compting b ACI (1) and EC 2 (2) codes at service load were presented in Table (2), it can be seen that, the predicted deflection wide beams calclated b 124

6 ACI (1) and EC 2 (2) codes were less than the experimental deflection b 19% and 21% on average respectivel. It can be explain this increasing in experimental deflection becase the dial gage was recorded the deflection in center wide beams in longitde and transferred directions and not consider the deflections at edges for centre beam. This case attribted to Saint-Venant s principle. Saint- Venant's states that in a bod nder the action a sstem forces which are applied in a limited region its bondar, the stresses and strains indced b those forces in another region the bod, located at a large distance from the region where the forces are applied, do not depend on the particlar wa the forces are applied, bt onl on their resltant. This "large distance" ma be considered, in most cases, as the largest dimension the region where the forces are applied (6). Table (2) Experimental deflection comparing with deflection compting b ACI (1) and EC 2 (2) Beam Specimens cods at service load Deflection at Service Load, (mm) Measred Predicted (mm) ACI 318M-14 EC 2 %Difference %Difference WBS WBP WBP WBP s 4.3 Strain characteristics in longitdinal reinforcement and compression face concrete specimens Table (3) shows the vales strain in middle longitdinal reinforcement bar and on parallel place concrete face (in compression) at ield and ltimate load that were obtained from strain gage connected to data logger Strain in longitdinal reinforcement It can be seen from Table (3) that the strain in longitdinal reinforcement at ield load is reglar gradation increasing in specimens WBP3-1 and WBP3-2 that sed the shear steel plate with 13% and 9% respectivel; this is obvios, de to the reglar gradation increasing spacing steel plate. At ltimate load the strain in longitdinal reinforcement for the specimens WBP3-1, is more than that for the specimens WBS b 27%, this ma be as a reslt constraint b the large nmbers closed hole in shear steel plate. B increasing the spacing for shear steel plate b 33% and 100%, the strain in longitdinal at ield load is reglar gradation decreasing in specimens WBP3-2 and WBP3-3 compared with WBP3-1 b 10% and 26% respectivel as a reslt redction ield load. Also at ltimate load the strain in longitdinal reinforcing decreasing in 125

7 specimens WBP3-2 and WBP3-3 compared with WBP3-1 b 74% and 28% respectivel. This ma be as a reslt redction in ltimate load. Indeed the experimental ield strength longitdinal steel reinforcement was 415MPa and the modls elasticit steel was MPa, so the experimental ield strain is and it can be seen from Table (3) that the experimental ield strain longitdinal reinforcement all specimens were above the theoretical ield strain. Beam Specimens Table (3) Strain characteristics in longitdinal reinforcement and concrete specimens Longitdinal Reinforcement Concrete (Compression) WBS WBP WBP WBP Strain in compression face concrete Based on Table (3), the strain in compression face concrete (at middle top face specimens) at ield and ltimate loads is increased for the specimen WBP3-1, WBP3-2 and WBP3-3 b 37%, 33% and 35% (at ield) and 15%, 92% and 22%( at ltimate) respectivel. B increasing the spacing for shear steel plate b 33% and 100%, the strain in compression face concrete was decreased for the specimen WBP3-2 and WBP3-3 b 3% and 1.7% (at ield load). For ltimate load stage, the strain in compression face concrete was increased for the specimen WBP3-2 compared with WBP3-1b 67%, bt it decreased for the specimen WBP3-3 b 32% as a reslt redction ltimate load. The strain prile for specimens is shown in Figre 6, 7, 8 and Strain characteristics in exterior and interior legs shear steel plate Table (4) shows the vales strain in exterior and interior legs shear steel plate at ield and ltimate load that were obtained from strain gage connected to data logger. It can be seen from Table (4) that the strain exterior leg shear steel plate is increased b 55% and 49% for WBP3-2 and WBP3-3 respectivel in comparison with WBS at ield load, bt it was decrease b 17% for WBP3-1. At ltimate load it is decreased b 62%, 28% and 46% for the specimenswbp3-1, WBP3-2 and WBP3-3 respectivel, compared with WBS. B increasing the spacing for shear steel plate b 33% and 100%, it can be seen from Table (4) that the strain in the exterior leg at ield load was increased in specimens WBP3-2 and WBP3-3 compared with WBP3-1 b 87% and 80% respectivel. And at ltimate load the strain exterior leg was increased in specimens WBP3-2 and WBP

8 Cross Section Wide Beam(mm) d=170mm Cross Section Wide Beam(mm) d=170mm Cross Section Wide Beam(mm) Cross Section Wide Beam(mm) Jornal Engineering and Sstainable Development Vol. 20, No. 05, September (ISSN ) compared with WBP3-1 b 92% and 46% respectivel. This increasing in strain at ield and ltimate load stages ma be de to the redcing action shear strength providing b shear steel plates as a reslt increasing distance between it kN 100 kn 150kN 200kN 250kN 300kN 350kN 400kN Yield 415kN 440kN Failre Strain Prile WBS Yeild Strain Long. Rein. Steel kN 100kN 150kN 200kN 250kN 300kN 350kN 400kN 420kN Yield 431 kn Failre Strain Prile WBP3-1 Yeild Strain Long. Rein. Steel Fig. (6) Mid span strain prile WBS specimen Fig. (7) Mid span strain prile WBP3-1 specimen kN 100kN 150kN 200kN 250kN 300kN 350kN 400kN Yield 410kN 420kN 430kN 441kN Failre Strain Prile WBP3-2 Yeild Strain Long. Rein. Steel kN 100kN 150kN 200kN 250kN 300kN 350kN 370kN Yield 376kN Failre Yeild Strain 20 Long. 10 Rein. Steel x Strain Prile WBP3-3 Fig. (8) Mid span strain prile WBP3-2 specimen Fig. (9) Mid span strain prile WBP3-3 specimen 127

9 4.4.2 Strain in interior leg shear steel plates It can be seen from Table (4) that the strain in the interior leg shear steel plate is increased b 88% and 2% for WBP3-2 and WBP3-3 respectivel(at ield load), bt it was decreased b 23% for WBP3-1. At ltimate load it was increased b 104% and 236% for the specimen WBP3-2 and WBP3-3 respectivel bt it was decreased b 46% for WBP3-1. B increasing the spacing for shear steel plates b 33% and 100%, it can be seen from Table (4) that the strain in the interior leg at ield and ltimate load stages the strain in interior leg was increased in specimens WBP3-2 compared with WBP3-1 b 60% and 280% respectivel. This increasing in strain at ield and ltimate load stages ma be de to the redcing action shear strength providing b shear steel plate as a reslt increasing distance between it. Bt for WBP3-3, the strain interior leg was decreased b 13% and 37% at ield and ltimate load stage respectivel. This decreasing in strain ma be de to the earlier sdden shear failre the specimen WBP3-3. There are two main isses are observed: 1. It is clear that the strain in interior leg is more than strain in exterior leg at ield load b 39%, 31%, 70%, for WBS, WBP3-1, WBP3-2 respectivel, bt it was decreased b 4% for WBP3-3, and at ltimate load the strain in interior leg is more than strain in exterior leg abot 23%, 76%, 248%, and 663% for WBS, WBP3-1, WBP3-2 and WBP3-3 respectivel. 2. B increasing the spacing b shear steel plate the strain in exterior and interior legs was increased except the strain in interior legs WBP3-3 becase the specimen was fail de to redction shear force strength. Table (4) Strain characteristics in shear steel plates (Exterior and Interior legs) specimens Beam Specimens Shear Reinforcement or Steel Plate(exterior leg) Shear Reinforcement or Steel Plate(interior leg) WBS WBP % % % % WBP % % % % WBP % % % % 4.5 Comparison between the ield and ltimate strain (nominal and experimental) steel plates Table (5) explains a comparison the ield and ltimate nominal strain and experimental strain in shear reinforcement (stirrps) and shear steel plate for interior leg. It can be seen that: 128

10 1. In all specimens the experimental strain at ield doesn't reached to the theoretical ield strain stirrps or plate except WBP3-2 specimen. 2. The experimental strain at ield load is less than theoretical strain b 43% for the specimen WBS while the experimental strain at ield load is less than theoretical strain b 37% and 17% for the specimen WBP3-1 and WBP3-3 respectivel, bt it was pper than the theoretical strain b 53% for WBP3-2. Spec. Table (5) Strain characteristics in shear steel interior plate legs f (MPa) f (MPa) Exp. exp. WBS WBP WBP WBP Crack Pattern The tested beams at different stages loading are shown in details in Plate (1). The bearing nmbers inside the circles represent the seqence formation the cracks, while the nmbers shown nder the beams between those representing the seqence are the cracks spacing. The sign (*) represents to the first crack width appeared. From these figres the following conclsions can be drawn: 1. De to the constant moment applied within the middle third the beam the seqence formation cracking was random, and cracks grew pward with the increase the applied load. 2. Cracks forming within the middle third the beams were generall vertical de to the pre moment applied on this part the beam. Otside this zone the cracks became inclined de to the presence shearing forces in addition to the moment. The specimen WBP3-3 was failed nder high shear action. When the diagonal crack occrs, there mst be a redistribtion internal forces at the cracked section. And when the beam has no web reinforcement, the external shear resisted b the concrete web mst be redistribted partl to the tensile reinforcement throgh dowel action bt mainl to the compression zone concrete. The redistribtion mst take place b the web reinforcement. For the WBP3-3 the failre was immediatel happen, it is possible interpreted that the member does not accept an redistribtion when the diagonal crack forms. In this case, the web reinforcement will ield immediatel and the compression zone will be destroed immediatel (7). 4.7 First crack width It can be seen from Table (6), the crack width the first crack at cracking and ield load. The first crack appeared randoml within the middle third the span (zone maximm moment), was not necessaril the widest one. The first crack width at cracking load is eqall in all specimens as a reslt the same properties concrete 129

11 and longitdinal reinforcing. Bt at ield load the crack width the first crack was decreased b 50% for the specimen WBP3-1 and increased b 62.5% for the specimen WBP3-3 compared for WBS specimen. Bt it can be seen that the nmber shear cracks is increased b 12.5% and 25% for the specimens WBP3-2 and WBP3-3 respectivel compare with WBS, bt it decrease b 25% for WBP

12 Plate (1) Cracking patterns specimens 4.8 Shear cracks spacing Contined- Plate (1) It can be seen from Table (6) that with increasing the spacing steel plates, the minimm spacing shear cracks was eqal with WBS bt it was increased b 20% for 131

13 the specimen WBP3-2 compared with others. And no significant effect for average crack spacing. B increasing the spacing for shear steel plate, the maximm spacing WBP3-2 was decreased b 15% compared with WBP3-1 as a reslt increasing shear cracks, bt for the WBP3-3 the maximm crack spacing was increased b 115% as a sdden shear failre. The average crack spacing was decreased for WBP3-2 and WBP3-3 b 12.5% and 17% respectivel compared with WBP3-1 specimen as a reslt increasing shear cracks. Table (6) First crack width, nmber and spacing shear cracks for specimens Beam Specimens 1 st Crack at Cracking 1 st Crack at Yield No. Cracks Shear Cracks(mm) Load (kn) Width (mm) Load (kn) Width (mm) Flex. Shear Min. Max. Average WBS WBP WBP WBP Comparison the first crack width compting b ACI 318M-14 (1) and EC 2 (2) codes It can be seen from Table (7), the experimental crack width the first crack at service and ield load comparing with predicted first crack width according the ACI 318M-14 (1) and EC 2 (2) codes. The experimental crack width all specimens at service and ield load was 0.13mm and 0.22mm on average. The predicted crack width at service and ield loads wide beams compting b ACI 318M-14 (1) and EC 2 (2) codes (0.21 and 0.33) mm and (0.12 and 0.19) mm on average respectivel. So it can be seen that: 1. The experimental crack width at service and ield load was less than predicted crack width compted b ACI 318M-14 (1) b 38% and 33% respectivel. 2. The experimental crack width at service was close to predicted crack width compted b EC 2 (2) bt it was pper b 16% at ield load. 3. From (1) and (2) above EC 2 (2) code was more conservative than ACI 318M- 14 (1). Table (7) Comparing experimental first crack width with crack width compting b ACI 318M-14 (1) Beam Specimens and EC 2 (2) cods at service and ield load Crack Width (mm) Experimental According ACI 318M- 14 At Service load At Yield load At Service load At Yield load According EC 2 At Service load At Yield load WBS WBP WBP WBP

14 4-10 Comparison the crack spacing compting b ACI 318M-14 (1) and EC 2 (2) codes Table (8) shows the measred and predicted vales crack spacing according to BS (9) and EC 2 (2) onl becase no sch formlas were proposed in other codes design (1). In BS (8), the average crack spacing approximatel eqal 1.67(h-x) for primar cracks, in this method the height netral axis determines the spacing cracks. It can be seen from Table (8) that: (1) The predicted mean crack spacing according to BS (8) ranged between 215mm and 224mm for all for wide beams tested. And the experimental average crack spacing ranged 91mm to 111 mm. B comparing the vales obtained experimentall and those predicted sing BS (8) formla, it can be seen that these vales are different from those obtained experimentall b 120% on average. (2) The predicted minimm and maximm crack spacing according to EC 2 (2), 92mm and 160mm respectivel all for wide beams tested. From Table (8) it can be seen that the EC 2 (2) formla did not consider the concrete compressive strength, ths for all the investigated specimens, the crack spacing were the same for beams with the identical reinforcement. This was not the sitation obtained experimentall; the minimm and maximm crack spacing was bonded b (40mm to 60mm), and b (51mm and 152 mm) respectivel. B comparing the vales obtained experimentall and those predicted sing EC 2 (2) formla, it can be seen that these vales are different from those obtained experimentall b 45% and 22% on average. A modification in the formlas proposed b BS (8) and EC 2 (2) are needed to consider the spacing shear reinforcement Comparison between the weights specimens It can be seen from Table (1) that sing the shear steel plates was redced the weight b 2.3%, 2.7% and 3.1% for specimens WBP3-1, WBP3-2 and WBP3-3. It is clear that sing shear steel plates is redced the weight specimens b 2.7%. Table (8) Comparing nmber cracks and experimental crack spacing with crack spacing compting b BS 8110 (8) and EC 2 (2) cods Beam No. Cracks Cracks (mm) Specimens Experimental According BS 8110 According EC 2 flexral Shear Min. Max. Average Mean Min. Max. WBS WBP WBP WBP

15 5. Conclsions and Recommendations 5.1 Shear steel plates is a good alternative for replacing stirrps (as web reinforcement) and gives identical reslt in ield and ltimate load (with increasing 5% ield load). 5.2 Althogh the specimen with shear steel plates gives an increase in deflection b 24% compared with that stirrps, bt it gives increasing in dctilit with 55%. 5.3 Using shear steel plate, redce the strain in exterior and interior legs b 17% and 46% compared with stirrps, althogh the ield strength shear steel plates is less than stirrps ield strength b 47%. 5.4 Using the shear steel plates instead stirrps redced the total weight wide beams b 2.7%. 5.5 B sing steel shear plates with 3mm thickness, with spacing between steel plates 125, 166 and 250 mm (increasing the spacing b 33% and 100%), it can be notified: The deflection at ield was increased b 2% and 16% respectivel The ield load redced to 5% and 12% respectivel The strain in longitdinal reinforcing was decreased b 10% and 26% respectivel at ield load The strain in exterior leg was increased b 87% and 80% respectivel at ield load and b 143% and 31% respectivel for the interior legs At ield: the strain in interior legs is more than the strain in exterior leg b 31%, 70% and 1% The nmber shear cracks is increased b 50% and 67% respectivel, so that the average crack spacing was decreased b 12.5% and 17% respectivel. 5.6 The predicted deflection wide beams compting b ACI (1) and EC 2 (2) codes were less than the experimental deflection b 19% and 21% on average respectivel. 5.7 EC 2 (2) code was more conservative than ACI 318M-14 (1) to predicted the crack width. 5.8 A modification in the formlas proposed b BS (8) and EC 2 (2) are needed to consider the spacing shear cracks. 6. References 1. ACI Committee 318M-14, 2014, Bilding Code Reqirements for Strctral Concrete and Commentar, American Concrete Institte, Farmington Hills, MI, 465 pp. 2. Erocode 2, 2004, Design Concrete Strctres Part 1-1: General Rles and Rles for Bildings (EN ), Eropean Committee for Standardization, Brssels, Belgim, Dec225 pp. 3. Adam S. Lbell, Edward G. Sherwood, Evan C. Bentz, and Michael P. Collins, 2006, One wa shear strength thick slabs and wide beams ACI Strctral Jornal, vol. 103, no. 6, Nov. - Dec pp. 134

16 4. Adam S. Lbell, Evan C. Bentz, and Michael P. Collins, 2009 Shear reinforcement spacing in wide members, ACI Strctral Jornal, vol. 106, no. 2, March - April, pp. 5. Mohamed M. Hanaf, Hatem M. Mohamed and Nabil A.B. Yehia, 2012, On the Contribtion Shear Reinforcement in Shear Strength Shallow Wide Beams Life Science Jornal vol. 9, no. 3, pp. 6. Ferdinand P. Beer E. Rssell Johnston, Jr. John T. De Wolf, Mechanics Materials", Lectre Notes: J. Walt Oler Texas Tech Universit, 2009, pp. 7. ACI-ASCE Committee 326, shear and diagonal Tension, (1962), 1-124pp , Strctral Use Concrete Part 2 Code Practice for Design and Constrction (B.S ), British Standard Instittion, London, P