Laced and Battened Columns, design of steel column

Raju Sharma Ass A ssii st staa n t Pr Prof ofee s so sorr Chandigarh University Mohali, Chandigarh

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Perforated cover plates are also used for this purpose. Perforated purpose . However How ever IS 800 do not give any spe specif cificat ication ion for the design of such plates. Lacings Rolled steel f lats and angles are are used for lacing. One can use single lacing or double lacing system. The object of providing lateral system is to keep keep the







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Instead of lacing one can use battens to keep members of columns at required distances







Design

Of laced

• As far far as possible ,the latticing latticing system shall be uniform throughout throughout • In single laced system the direction of lattices or opposite faces should be shadow of the other. It should not be mutually opposite

• In bolted/riveted construction, the minimum width of lacing bars shall be three times the nominal diameter of the bolts/rivets • The thickness of flat lacing bars shall not be less than 1/40 th of its effective length for single lacing and 1/16th of the effective length for double lacings • Lacing bars shall be inclined at 40 º to 70º to the axis of built up member • The distance b/w the two main members should be kept so as to get ryy > rzz where ryy is the R.o.G about weaker axis and rzz is the R.o.G of stronger axis of individual member • Maximum spacing of lacing bars shall be such that the maximum slenderness of the main member b/w consecutive lacing connection is not greater than 50 or 0.7 times the most unfourable selenderness ratio of the member as a whoel. • The lacing shall be designed to resist transverse shear vt = 2.5% of axial force in column.if there







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Batten plates should be provided symmetrically symmetr ically At both both ends batten batten plates should be pro provided. vided. They should be provided at point where the member is stayed in its length. The number of battens should be b e such that the member is divided into not less than three bays b ays as far as they should be spaced and proportioned uniformly throughout. Battens shall be of plates, angles, channels, or I-secti









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The effective slenderness ratio of battened columns shall be taken as 1.1 times the maximum actual slenderness ratio of the column, to account for shear deformation. The vertical spacing of battens, measured as centre to centre of its end fastening, shall be such that the







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In case columns are subjected to moments also , the resulting shear force should be found and then the design shear is sum of this shear and 2.5% of axial load The design sher and moments for battens plates is given by. V b V x C/NS V V x C/ 2N at each V and M







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Effective depth of intermediate i ntermediate battens shall not be less les s than ¾ th t h of the above distance. In no case the width of battens b attens shall be less than twice the width of one member memb er in the plane of the th e batten. It is to be noted that the effective depth of the batten shall be taken as the longitudinal longitudin al distance b/w the outermost







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Connecting two pieces of sections to get the required length of column is called column splicing. In multistory building, the section of the column may be changed from storey to storey for economy. This also







Placed fir firmly mly in contact with each other and hence considerable load is transferred by bearing. The connections and splice spli ce plates are designed for only 50% of axial load. The situation situati on in which various types of column splices are are used.















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Where a is the distance between centr centree to centr centree of







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(1/6)bt² f bsbs = M

Laced and Battened Columns, design of steel column

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