ART $2122-$ STRUCTURES I

Assignment #$6$

$52$ points

For the following problems, indicate the given values of $P,A,$ or $f$ and solve for the missing value

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A wrought iron bar sustains a tensile force of $40$kips. If the allowable tensile stress is $12$ksi, what is

the required cross$-$sectional area of the bar? $(4$ pts$.)$

A short square timber post supports a load of $115$kips. If the allowable compressive stress is $1000$

psi, what nominal$-$size square timber should be used? $(5$ pts$.)$

How much stress is on a steel bar with cross$-$sectional dimensions of ${1\mathrm{.}25}^{\text{'}\text{'}}1\mathrm{.}75"$ while carrying a

tensile load of $82$ kips? $(5$ pts$.)$

A steel bolt with a diameter of $0\mathrm{.}75$ in$.$ is to be used in a joint similar to that in Figure $2\mathrm{.}26$b$.$ What is

the maximum permissible load on the joint if the allowable shear stress in the bolt is $.$

Determine the minimum cross$-$sectional area of a steel bar required to support a tensile force of $50$

kips if the allowable tensile stress is $20$ ksi. $(4$ pts$.)$

What axial load may be placed on a short timber post whose actual cross$-$sectional dimensions are

${9\mathrm{.}5}^{\text{'}\text{'}}{9\mathrm{.}5}^{\text{'}\text{'}}$ if the allowable unit compressive stress in the wood is $1100$ psi? $(4$ pts$.)$

A short concrete pier, ${18}^{\text{'}\text{'}}{18}^{\text{'}\text{'}},$ supports an axial load of $150$ kips. Based on allowable stress, $F_c=$

$900,$ is the construction safe? $(6$ pts$.)$

What force must be applied to a steel bar that is $1in.$ square and $2ft$ long to produce an elongation

of $0\mathrm{.}016$ in$.?(4$ pts$)$

How much will a nominal $8^{\text{'}\text{'}}{8}^{\text{'}\text{'}}$ Douglas fir post shorten under an axial compression load of $45$kips

if the post is $12ft$ high? Use $E=1500$ ksi. $(7$ pts$.)$

A $\frac{1}{2^{\text{'}\text{'}}}$ diameter round steel rod $40ft.$ long supports a load of $4$ kips. How much will it elongate? $(8$

pts$.)$