Question 1. A single span beam which carries a uniform load of 26kN/m has an unsupported span of 4m. It is made up of Yakal 200 x 350mm wooden section. It is subjected to a compressive load of 400kN at its centroid. Allowable stresses of Yakal using 80% stress grade are found in the NSCP code for timber structure. The beam is fixed at both ends. A. What is the value of the allowable bending stress with slenderness factor correction? B. What is the allowable compressive stress? C. Is the member safe, unsafe or not allowed by the code?

Solution:-\rightarrow According to NSCP code for timber(a) maximum bending strees of YAKAL =24.50 \mathrm{MPa} with 80 \% selenderness carrection factor \rightarrow allowubl bending strers =24.80 \times 0.8=19.84 \mathrm{MPa}(b) maximum compressive load =15.8 \mathrm{MPa}allowable compressive load =15.8 \times 0.8=12.64 \mathrm{MPa}(C) check for compressive stress\rightarrow \text { compressive load }=4 \text { cour }\rightarrow comprerive spres = Compressive loadArea of crossection\begin{aligned}\rightarrow \text { compressive stress } &amp; =\frac{400 \times 1000}{200 \times 350}=5.7 \pm \mathrm{N} / \mathrm{mm}^{2} \\&amp; =5.71 \mathrm{MPa}<12.64 \mathrm{MPa}\end{aligned}\rightarrow check for Bending compressivestress\rightarrow Bending moment diagram of beam\begin{array}{l}\rightarrow \text { maximum the Bendingmoment }=\frac{\omega l^{2}}{24}=\frac{26 \times 4^{2}}{24} \\=17.33 \mathrm{kN}-\mathrm{m} \\\end{array}\rightarrow maximum - ve Bending moment =\frac{\omega l^{2}}{12}=\frac{26 \times 4^{2}}{12}=34 \cdot 67 \mathrm{kN}-\mathrm{m}\rightarrow maximum Bending moment on the beam =34.67 \mathrm{ur}-\mathrm{m}\rightarrow So maximum Bending stress \left(f_{b}\right)\begin{array}{l}f_{\text {bmax }}=\frac{B M_{\text {max }}}{I} \times y_{\text {amax }} \\f_{\text {max }}=\frac{39.67 \times 10^{6} \mathrm{~N}-\mathrm{mm}}{200 \times \frac{350^{3}}{12}} \frac{350}{2} \mathrm{~mm} \\f_{\text {bomax }}=8.99 \mathrm{mPa}\end{array}\sum_{\frac{m}{I} x y}^{200}but allowable bending strees is 19.84 \mathrm{MPa}\rightarrow Hence beam is safe in both compresion as well as in Bending: ...