Question

Question 2 Picture it. It's 5 o'clock on Friday and at the end of a long week all Dave wants to do is go home. But his boss has other ideas; he tells Dave that he can go once he has designed the tension reinforcement for the beam in Figure 2. a) Design reinforcement for this beam and check its suitability b) If the length of the beam is reduced to 7m, can the amount of reinforcement also be reduced? If so, what is a sensible amount of reinforcement? Points to consider: • Are you designing the beam for the serviceability or ultimate load? Why? . Could other diameter bars have been used? How would this affect the beam? • What other factors will affect the amount of longitudinal reinforcement in the beam? w, kN/m 12m Figure 2 Design Data: Grade of steel, fx = 500MPa Grade of concrete, fck = 30MPa Dead load (incl. self-weight of beam) = 10kN/m Imposed load = 5kN/m • Overall cross-section of the beam =550 x 250mm Dry or low air-humidity conditions LKW Cover = 25mm

i have also attached the solutions.

could you please explain step by step what they are doing. especially the bit in part (a) where they do x/d

Answer 1

While deegning the bear he f the f denforcenent Cateel) to caleulate the amount stp. beam and Caleulate the load. are :- There two tpe of load on a beam Dead load The we ght f the beam italf b) Lve Load The extenal load the beam In the problem, 10kN/m Dead Load Live Load 5kN' # Lad beam. Caleulabona the bean the is gren per mehe lengith of done pe metre langth g Design load is lve load. he sun of dead load and Dead load t Live Load 10 Sauncab ly load %3D %3D IS EN/m load is Sauicability le load Sum of dead load and desig the what a beam, wve kighan load ha he find Ultimate load deugung #Whle beam fo acting so we beam for lafet on is pupeses,

NAimate Load 1.35 x Dead load + 1. Sx Live load. 21EN/m. %3D 1.35 x 10 1.5x S Oltmate load do the design f Lighe load for which the beam. y Caleulate Bending Moment and Shear oce Simply duppoked beam so, fa Bending The beam fomula the is Moment for and wl. Shear fore = Cltimate Lond x (Legih ofBe larmum Bending Moment %3D 8. wl 8. %3D Legdh f he Boan 2. Ultimate Cond x lanimum Sheau focce %3D wl 2.

Efeetive DepR Calculation Renforcenent Cormpreon Reinfecement Cteoion) Shean lnka / shiraps Concete cover Effective depth g a the beam tesion' steel du tane from is the * he top of the beam It given by d. d= Total depth %3D Clear Cove - Dianeten of -1/Lngrhdnal 2 Penfouene Bais f the beam Shear links 550 25-8 (0Sx25) %3D beam= 550 x 25o mm depth x width the S3 %3D to tal depth - SSO mm a beam the problem the Clear Care 14 assumed Concet Cove providad be 25 mm to in SHAups a beam Shaa links or the steel bas to be component that hold The diamete io anune are in

Check Remforcement aesuning yiolded steel Las In thes step until the calculated moment The be bending ealculate steel has Bendng we the yelded to has moment Maninum then The fomula more Moment the Bendy Med %3D Ed file where Area h the Steel of 25mm problom, a ba gf and the nunbe of bas used 6. is From the bai chart As= 2945. ty= yield thrength of steel. fe 500 the steel used %3D so f = So0 Hee ffecbre depe of the beam breadth of bean Compressive strength of conceete which cakulated to than greate be 453 kNm MRd is Bending Mome or man shay. is it Manimum so,

nforcement Raho Check This cheek -ent dore to caleulate the remforcom ratio beam beam and detkimne if the Jenfred in under roinfolced Over or The reciomended value of ronfoeonet beam The value code book of dfferent from vaies countries s reccomended countries the in fomula Renfocemet Rahio The Area of steel breadk x depth of beam 2.34 Y. which is over leinfore é uoually Aq = 0.001A. The receommended value goven by Calculate he netral ans Naw, we where Q beam a pont bending Neutral there no 1 92 A 377mm neutral a beam the raho of in the effecetine dyed to 0.747 0.747 for the yield of steed

Eg -X 1- 0.0035 0. 00 22 %3D 0.0035 -1 0 0022 0.591 the so steel la not ypielded 500 0.0022 %3D X 2 X 1os Y, = Facto of safety 1.1. 0.0035 0.60189 The steel han nt yrelded Eg < Ey the foces in Stee and concete i fou to Cakulale Inally M6 Rd MERd > Mman
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