Problem $1.$ Bolted Connection Evaluation

A rolled $150$x$100$x$10$ UA made of Grade $350$ steel is connected by two rows of Grade $8\mathrm{.}8$ M $24$ X $($refer to page $154$ for definition of X $)$ bolts in the $150$ mm leg and one row in the $100$ mm leg as shown in Figure $1.$

Figure $1.$ Section and bolts configuration $($not to scale$)$

Hints:

$1-$ The gauge lengths are from attached Table $2\mathrm{.}8$: Gauge lines for angles of course reader $($Use the unbracketed values based on nominal leg length and ignore the bolt size when finding $S_{gi}).$

$2-$ Refer to UA strength properties at the end of course reader to find $F_y($from tables$)$ and $F_u($From their end notes$)$

$3-$ To find $f_{uf}$ and $f_{yf}$ Refer Bolt Strength table attached on the last page of this homework.

$4-$ When referring to Table $9\mathrm{.}6\mathrm{.}2,$ note that Steel Angles are specified as Rolled Edges.

Find:

a$)$ Whether or not the connection meets code and construction requirements:

i$).$ What is the minimum required distance from the center of the hole to the edge in any directions based on clause $9\mathrm{.}6\mathrm{.}2$ NZS $3404?($Do not consider the force requirement of Eq $9\mathrm{.}3\mathrm{.}2\mathrm{.}4(2))$ NZS $3404$

ii$).$ What is the maximum permissible distance from the center of the hole to the side edge based on clause $9\mathrm{.}6\mathrm{.}4$ NZS $3404?$

iii$).$ What is the actual distance from the center of the hole to the edge in the short and long legs?

iv$).$ What is the minimum required bolt hole centerline spacing not considering force $($Based on clause $9\mathrm{.}6\mathrm{.}1$ NZS $3404)?$

v$).$ What is the actual minimum bolt hole center spacing in the direction of applied force?

vi$).$ For construction, what is the minimum required distance between the bolt hole center and the inside face of the angle if a heavy impact wrench is used without an extension bar? $($Based on Figure $6\mathrm{.}8$ of the course reader$)$

vii$).$ What distance is minimum provided between the bolt center and the inside face of the angle in the long and short legs respectively?

viii$).$ For construction, what is the distance between the bolt centres in any directions required if an impact wrench is used?

b$)$ Assume a bearing$-$type connection and fracture through two holes governs with a tensile force $N_t=800$ kN $.$

ii$).$ What is the capacity$/$bolt considering bolt spacing in the line of force given in Eq$.9\mathrm{.}3\mathrm{.}2\mathrm{.}4(2)$ NZS $3404($For this question when calculating a$\_$e$,$ consider clear distance between bolts plus df$/2)?$

iii$).$ What is the nominal bearing capacity of the ply for non$-$seismic design based on clause $9\mathrm{.}3\mathrm{.}2\mathrm{.}4\mathrm{.}1$ NZS $3404?$

iv$).$ What distance is needed between the hole centre and the end of the plate so that end distance satisfies the strength requirement obtained in part ii$)?($Consider Eq $9\mathrm{.}3\mathrm{.}2\mathrm{.}4(2)$ NZS $3404)$

c$)$ Calculate the force at which slip is likely to occur in the connection if it were designed as slip critical $($for clean as rolled surfaces and standard holes as per clause $9\mathrm{.}3\mathrm{.}3).$

Problem $2.$ Bolted Connection Design under Shear and Tension

A T$-$section cut from $250$UC$72\mathrm{.}9$ is connected to a column using $4$ bolts $($M$24$X$,$ Grade $8\mathrm{.}8)$ as shown in Figure $2.$ Assuming that the members are adequate $($no plate bearing and block shear failures$)$ and that prying action is not significant:

a$)$ Determine the maximum factored load, $P^{**},$ based on combined failure, if a bolts act in bearing mode.

b$)$ Determine the maximum service load, $P_S,$ based on serviceability consideration if bolts act in a slip$-$critical $($friction$)$ mode. $($clean as$-$rolled surfaces, standard holes$).$

c$)$ If the contractor uses M$24$N bolts $($Grade $8\mathrm{.}8)($instead of M$24$X Grade $8\mathrm{.}8),$ can a bearing mode still carry the factored load based on serviceability design criteria in Part $($b$)?$ Check the ratio for bolt combined failure. The governing load combination is $P^{**}=1\mathrm{.}5P_S$