QUESTION $4(130$ marks$)$

As indicated in Fig. $4,$ two splice plates of Grade $300$ steel with a thickness of $12$ mm each, are connected

together. There are $3$ lines and $n$ rows of bolts on the connection. If grade $8\mathrm{.}8$ S snug tight M $16$ bolts are used TABLE $8$

DESIGN AREAS OF BOLTS

$\backslash$table$[[\backslash$table$[[$Nom$.$ dia.$],[($mm$)]],$Designation,Areas $($mm$^(2))],[$d$\_($f$),$A$\_($c$)$ core,$\backslash$table$[[$A$\_($s$)$ tensile$],[$stress$]],$A$\_($o$)$ shank$],[12,$M$12,76\mathrm{.}2,84\mathrm{.}3,113],[16,$M$16,144,157,201],[20,$M$20,225,245,314],[24,$M$24,324,353,452],[30,$M$30,519,561,706],[36,$M$36,759,817,1016]]$ TABLE $10$

STRENGTH LIMIT STATE HIGH STRENGTH STRUCTURAL BOLTS $\frac{8\mathrm{.}8}{S},\frac{8\mathrm{.}8}{T}B,\frac{8\mathrm{.}8}{?}$ TF BOLTING CATEGORIES $(f_{ut}=830$MPa$)$

NOTE: The above table lists the design capacity of a ply in bearing for Grade $250(f_{vp}=410$MPa $)$ plate only. For design capacities for ply failure in other grades of steel, multiply the above values by the ratio of the actual $f_{wp}$ to $410$ MPa $.$

SHEAR$-$TENSION INTERACTION DIAGRAMin this connection, and the plane between the splice plates coincides with the threaded part of the bolt

$($threads included in shear plane$).$ The yield stress of the $12$ mm plate $f_y=310$MPa.

$($a$)$ Determine the minimum number $(n)$ of rows of bolts required for a design axial tension of $N^{*}=700kN$

$($You can use the Bolt Capacity Table attached to this exam paper$).$

$($b$)$ Check the bolts capacity in shear based on the number of bolts you have chosen $($DO NOT use bolt

capacity table $-$ use Sec $9\mathrm{.}3\mathrm{.}2).$

$(30$ marks$)$

$($c$)$ Check the ply in bearing on the splice plate $(=0\mathrm{.}9).$

$($d$)$ Check the section design capacity in tension for the splice plate.

$(40$ marks$)$

Design areas of bolts are attached to this exam paper.

Fig. $4.$ Bolted lap splice connections.

$d_h=$ hole diameter $=d_1+2mm,d_1=$ bolt diameter, $s_p=$ bolt pitch, $a_e=$ distance from hole edge to an edge in

the direction of a component of force plus half the hole diameter.