Frame
INTRODUCTION
SAFETY AND PRECAUTION
OBJECTIVE * To determine the horizontal rection at the pinned support for portal frame subjected to point loads and distributed * To study the behavior of a portal frame under different end conditions.
THEORY
-Structures are categorized as statically determinate or as statically in determinate. Determinate structures can be analysed additional conditions to solve. The portal frame is an indeterminate structure to several degree of indeterminacy depending on the end conditions To know the behavior of any frame it is advisable to know its different deflected shapes under different loading condition, which can be obtained by vertical work energy method analytically. Portal structures similar to the end portals of bridge have as their primary purpose, the transfer of horizontal loads applied at their top to their foundations. Clearance requirements usually lead to the use of statically indeterminate structure layout for portals, and approximate solutions are often used in their analysis. Consider the portal shown in all the member of which are capable of carrying bending and shear as well as axial force. The legs are hinged at their base and rigidly connected to the cross girder at the top. This structure is statically indeterminate to the first degree; hence, one assumption must be made. Solution of this type of structure based on elastic considerations, show that the total horizontal shear on the portal will be divided almost equally between the two legs; it will therefore be assumed that the horizontal reactions for the two legs are equal to each other and therefore equal to P/22. The remainder of the analysis can now be carried out by static .The vertical reaction on the right leg can be obtained by taking moment about the hinge at the base of the left leg. The vertical reaction on the left leg can then be found by applying Σfy= 0 to the entire structure. Once the reactions are known, the diagrams
SAFETY AND PRECAUTION
OBJECTIVE * To determine the horizontal rection at the pinned support for portal frame subjected to point loads and distributed * To study the behavior of a portal frame under different end conditions.
THEORY
-Structures are categorized as statically determinate or as statically in determinate. Determinate structures can be analysed additional conditions to solve. The portal frame is an indeterminate structure to several degree of indeterminacy depending on the end conditions To know the behavior of any frame it is advisable to know its different deflected shapes under different loading condition, which can be obtained by vertical work energy method analytically. Portal structures similar to the end portals of bridge have as their primary purpose, the transfer of horizontal loads applied at their top to their foundations. Clearance requirements usually lead to the use of statically indeterminate structure layout for portals, and approximate solutions are often used in their analysis. Consider the portal shown in all the member of which are capable of carrying bending and shear as well as axial force. The legs are hinged at their base and rigidly connected to the cross girder at the top. This structure is statically indeterminate to the first degree; hence, one assumption must be made. Solution of this type of structure based on elastic considerations, show that the total horizontal shear on the portal will be divided almost equally between the two legs; it will therefore be assumed that the horizontal reactions for the two legs are equal to each other and therefore equal to P/22. The remainder of the analysis can now be carried out by static .The vertical reaction on the right leg can be obtained by taking moment about the hinge at the base of the left leg. The vertical reaction on the left leg can then be found by applying Σfy= 0 to the entire structure. Once the reactions are known, the diagrams