COECTIOS Boled Column Splice wih Minor Axi Bending Auhor: Zahid Hamid, Kevin Cowie Affiliaion: Seel Conrucion ew Zealand Inc. Dae: 19 h February 015 Ref: CO310 Key Word Splice, Boled Splice, Boled Column Splice, Minor Axi Splice Inroducion In muliory conrucion column plice are provided for convenience of fabricaion, ranpor and erecion. If required he plice are locaed ju above he floor level, which enable eay acce o he join. There are wo ype of plice connecion, full conac bearing and non-bearing. A he name ugge in bearing plice he axial load i ranferred direcly o he column below by full bearing conac, bol and plae are inended o hold column in place. In non-bearing plice he load i ranferred hrough bol and plice plae. The deign of boled column plice wih minor axi bending momen, ie wo way momen reiing frame, i a complex proce. There i no much lieraure available on hi opic. A deign guide ha briefly dicue hi opic i he Souh African Iniue of Seel Conrucion Srucural Seel Connecion Guide or he Green Book. Anoher ource of guidance i he Seel Conrucion Iniue Publicaion 07, which cover he nonbearing plice wih minor axi bending. Thi aricle will cover deign of bearing and non-bearing plice connecion wih minor axi bending baed on he procedure oulined in he aforemenioned guide, and relae he deign equaion o ZS 3404. Bearing Splice (Full Conac) Thi ype of plice i he impler, he load from upper column i ranferred o he lower column hrough direc bearing, and he bol and plice plae are inended o hold he wo member in place. Figure 1 how force on he flange of column due o he minor axi bending in a full conac bearing plice. = c/ and M = M y/, are he axial compreive force and bending momen per flange. oe bol on he boom member are removed for clariy. The dimenion ε or b, denoe he par of flange ha will be in compreion (Figure 1) (SAISC, 01), wih he bearing capaciy deermined a per ZS3404 Eq. 5.13.3.1(1), given a Eq. 1 herein: R 1.5 f by f y f = Thickne of flange f y = Seel Yield Srengh Eq. 1 From verical force equilibrium: f y R.5 f Eq. Figure 1: Force/Flange of Column Due o Minor Axi Bending Diclaimer: SCZ and he auhor() of hi documen make no warranee, guaranee or repreenaion in connecion wih hi documen and hall no be held liable or reponible for any lo or damage reuling from he ue of hi documen Seel Conrucion ew Zealand Inc. 015 1
R = Combined reulan force in he furhe line of bol. R.5 ffy Eq. 3 ow aking momen abou X: bf b f g M R 0 Eq. 4 From ubiuing R from Eq.3 in Eq. 4, he following expreion i derived for ε: 4.5 f f y 1.5 f b f y f g g M Eq. 5 Inpu he value of ε from Eq. 5, ino Eq. 3 o deermine he magniude of he combined force, R in he furhe line of bol ha mu be reied by all bol on ha line. If Eq. 3 yield a negaive anwer, hen he minor axi bending doe no govern (SAISC, 01). Seel Conrucion ew Zealand Inc. 015
Worked Example Conider a 50 UC 90 column wih following deign acion: Axial Compreion Minor Axi Bending Axial Compreion/flange Minor Axi Bending/flange c My M 750k 100km 375k 50km Column Properie Flange widh Flange Thickne Yield Srengh Bol Gauge bf f fy g 56mm 17.3mm 300MPa 140mm Deermine he flange compreion widh, ε: 3.5ffy 0.9x.5x17.3x300 11.68x10 mm 1.5 f b 0.9x1.5x17.3x300 56 140 31x10 f y f g g 6 140 6 M 50x10 375000 76.5x10 mm 4 3 3 3 6 31x10 31x10 4x11.7x10 x76.3x10 41.8mm 3 x11.7x10 f y R.5 f 0.9x.5x41.8x17.3x300 375000 113k 3 Each line of bol mu rei 113k load. Seel Conrucion ew Zealand Inc. 015 3
on-bearing Splice In non-bearing plice connecion, i i generally aumed ha no conac exi beween he wo column, and any bearing beween hem i ignored. Thee plice are deailed wih a gap beween he column. All axial load and momen i o be ranferred o he lower column hrough he bol and plice plae. A ypical non-bearing column plice i hown in Figure. Unlike bearing plice he load i no equally hared by he all bol and here will be ome remoe bol() which carry more load. The load on each bol in hi cae i derived from he bol group geomery. SCI Publicaion 07 provide guideline on deermining he wor reacion on he remoe bol. Figure : Column Splice wih Minor Axi Bending & Maximum Bol Reulan b if Splice plae widh d h Bol hole diameer a e1, & a e3 Edge diance, a defined in Figure Becaue of he ymmery of he bol group geomery hown in Figure, by inpecion he boom lef bol i loaded more han he oher 5 bol, hi would revere if he load are revered. If he bol group i no ymmerical he force on each bol hould be deermined o verify he wor load on bol. Flange Plae The flange plice plae mu aify he following equaion: f M M 1.0 Eq. 6 = Maximum axial force/flange (Could be Tenion or Compreion) f = Axial capaciy of he plae (baed on ne area minu bol hole dia) M = Maximum weak axi bending/flange M = Bending capaciy of he plae (baed on ne Secion Modulu minu bol hole dia) Seel Conrucion ew Zealand Inc. 015 4
I i no neceary o carry ou hi check, if he flange plae are equal, wih repec o area & modulu, o he flange ielf and he eel grade are he ame (SCI P-07, 1997). Bol Hole Diameer d h = d + mm For d 4 d + 3mm For d > 4 Where d = diameer of bol. Maximum Bol Force The maximum reulan force on bol i calculaed a per Eq. 7: x y x y re R r r r r co V Eq. 7 r r y x n M Z b n = number of bol Z Elaic modulu of bol group b pf = bol cenre cenre diance = Angle from he cenre of bol group o he remoe bol (ee Figure ). V re = Reulan bol hear and bearing capaciy, which i he le of: a) The lip reiance of he bol per inerface, if TF connecion b) The bearing capaciy of he bol in he flange plae(), reduced where required by bol hole earing for he reulan end diance c) The bearing capaciy of he bol in he flange, reduced where required by bol hole earing for he reulan end diance. Reference SAISC, Srucural Seel Connecion, The Souh African Iniue of Seel Conrucion, Johanneburg, Souh Africa, 01. SCI, Join in Seel Conrucion Momen Connecion, he Seel Conrucion Iniue Publicaion 07, London, UK 1997. SZ, Seel Srucure Sandard (Incorporaing Amendmen 1 and ), ZS 3404:1997, Sandard ew Zealand, Wellingon, 007. Seel Conrucion ew Zealand Inc. 015 5