Module 9 Worked Examples: Steel Connections and Base Plates

A bolt has nominal area $A_b=353\text{ mm}^2$ and the applicable nominal shear stress is $F_{nv}=330\text{ MPa}$. Determine nominal shear strength for one shear plane.

Using the bolt from Example 1, what is the idealized nominal bolt shear resistance if the connection provides two effective shear planes and the provision permits direct multiplication?

A connection is designed for bearing-type strength. Does that statement by itself prove the bolts are installed only snug-tight?

Find the effective throat of an $8\text{ mm}$ equal-leg fillet weld.

A fillet weld has $F_{EXX}=490\text{ MPa}$, effective throat $5.66\text{ mm}$, and effective length $150\text{ mm}$. Determine the nominal weld-metal strength using $R_n=0.60F_{EXX}A_{we}$.

A $300\text{ kN}$ shear is assigned equally to four bolts, giving $75\text{ kN}$ per bolt. What additional checks remain?

A bracket load acts away from the centroid of its bolt group. Why is equal shear per bolt insufficient?

A concentric column reaction is increased while base-plate area remains unchanged. What happens to average bearing pressure and plate bending demand?

A column base develops enough overturning moment that one side of the plate tends to lift from the concrete. Can the concentric bearing-only model be used?

An architect wants a visually seamless HSS-to-HSS node. List the engineering questions that must be resolved before hiding the connection.

A four-bolt group has bolt coordinates $(\pm50,\pm75)\text{ mm}$ from its centroid. A vertical shear $V=40\text{ kN}$ acts with horizontal eccentricity $e=200\text{ mm}$. Using the elastic bolt-group method for this worked case, estimate the largest resultant bolt force.

A rectangular base plate has $B=500\text{ mm}$ in the eccentricity direction and $N=400\text{ mm}$ perpendicular to it. A compressive resultant $P_u=900\text{ kN}$ acts at $e=120\text{ mm}$ from the plate centerline. Use the simplified rigid-plate compression-only contact model.

A $400\text{ mm}\times400\text{ mm}$ base plate bears concentrically on a geometrically similar $800\text{ mm}\times800\text{ mm}$ concrete support with $f'_c=28\text{ MPa}$. Determine the nominal concrete bearing strength benchmark.

A bearing-type bolt has problem-supplied $F_{nt}=620\text{ MPa}$ and $F_{nv}=372\text{ MPa}$. Under LRFD, the required bolt shear stress is $f_{rv}=100\text{ MPa}$. Use $\phi=0.75$ and nominal bolt area $A_b=245\text{ mm}^2$.

A concentrically loaded W-column base is checked on the LRFD basis. The factored compression is $P_u=900\text{ kN}$, the plate is $B=400\text{ mm}$ by $N=500\text{ mm}$, the plate yield stress is $F_y=250\text{ MPa}$, and the column dimensions used by the AISC 14th Edition Manual Part 14 geometry are $d=300\text{ mm}$ and $b_f=250\text{ mm}$. For this worked case, the Manual-defined $\lambda n'$ branch has already been evaluated and is no greater than the $m$ or $n$ projections.