Concrete Helical Stair Design

Transcript

  Structural design………………………………………………………….ceng 501 Project on design of helical staircases i   Table of content Acknowledgement ……………………………………… Index ……………………………………………………. 1. Introduction.................................................................. 2 . Literature survey………………………………………  2.1 Definition……………………………………………… 2.2 Terms in stair…………………………………………... 2.3 Essential requirement………………………………….. 2.4 Classification of stair ………………………………….. 2.4.1 Based on material of construction………………. 2.4.2 Based on type……………………………………. 2.5 helical stair……………………………………………. 2.5.1 Geometric stair…………………………………. 2.5.2 Spiral stair……………………………………… 3. Design procedures ……………………………………… 3.1 Design procedure of geometric stair…………………... 3.2 Design procedure of spiral stair………………………… 4. Result and discussion ……………………………………… 4.1 Design of geometric stair……………………………… 4.2 Design of helical stair…………………………………. 5. Recommendation and future work  …………………………. 6. Reference …………………………………………………...  Structural design………………………………………………………….ceng 501 Project on design of helical staircases ii  Acknowledgement Of all, our deepest appreciation goes to our instructor Mr.Mebrehatom G. for getting us acquainted with civil engineering concepts through this mini project as part of structural design. And also we would like to thank our advisor Mr. Ashenafi and Mr.yonas for their unlimited support from the begging of the project to this final form. And of the last but not the least appreciation goes to our classmates for giving us some advice from the preparation till the edition of the project.  Structural design………………………………………………………….ceng 501 Project on design of helical staircases iii  Index a s… ............................................ Area of standard diameter reinforcement A s …………………………….. Total area of reinforcement calculated Ac …………………………… area of concrete B… …………………………. width of the strip C c ……………………………. concrete cover D …………………………….. Over all depth d 1 ……………………………. minimum depth requirement for deflection d 2 ……………………………. depth required for flexure d l ……………………………. dead load E c …………………………… strain in concrete E s …………………………… strain in steel f  cd … …………………………. design compression strength of concrete f  yd … ………………………… design yield strength reinforcement f  yk ………………………….. Characteristic yield strength of reinforcement   H  …………………………… room height S  …………………………… spacing of reinforcing bars le …………………………… effective length W …………………………… distributed load l l   ……………………………. live load P d …………………………… design load Φ . ............................................. Diameter    of the reinforcing bars   γ s …………………………….. Partial factor of safety for steel γ c  …………………………… partial factor of safety for concrete γ  ……………………………… unit weight ρ  b  ……………………………… effective geometrical ratio for reinforcement  Structural design………………………………………………………….ceng 501 Project on design of helical staircases iv Φ m   … .......................................... mess reinforcement diameter 2 θ  ……………………………… subtended angle α ………………………………… inclination angle A eff  ……………………………… effective area h eff  ……………………………… effective height d eff  ……………………………… effective diameter U eff  ……………………………… effective perimeter T c ………………………………. Torsional capacity of concrete T Rd ……………………………… Torsional resistance T sd ……………………………... designed torsionsonal moment V c   ……………………………… shear capacity of concrete V Rd ……………………………... shear resistance V sd   …………………………….. Design shear force B t ……………………………….. Correction for torsion B v ………………………………..correction for shear