Consider the framing plan below with an elevator shaft measuring ${10}^{\text{'}}-0^{\text{'}\text{'}}{10}^{\text{'}}-0^{\text{'}\text{'}}.$ Assume a Live Load of $150$ PSF and Dead Load of $90$ PSF$.$

a$.$ Calculate the tributary width for each beam. $(5$ pts$)$

b$.$ Calculate the end reactions for each beam. $(15$ pts$)$

c$.$ Draw a Free Body Diagram $($FBD$)$ and calculate the end reactions for each girder. $(20$ pts$)$

d$.$ Calculate the total axial reactions in columns C$3$ and C$4.(10$ pts$)$