KNOWLEDGE BASE REQUIRED: CONTINUOUS .VS. SIMPLE_SUPPORT KNOWLEDGE BASE REQUIRED: STRENGTH OF MATERIALS STEEL DESIGN TIMBER DESIGN SOIL MECHANICS WE COVERED: AREA AND CENTER OF GRAVITY Itotxx = Ixx + Ay2 SECTION MODULUS RADIUS OF GYRATION SOLVED ONE PROBLEM

MECHANICS OF MATERIAL BEHAVIOR: WE REVIEWED STATICS: DEFLECTION COMPUTATIONS SOLVED DEFLECTION PROBLEM DUE TO LOAD DUE TO THERMAL EXPANSION WE REVIEWED FLEXURE:

REVIEW OF STATICS (CONT’D) MOMENT -SHEAR DIAGRAMS SAMPLE PROBLEM

SOLUTION

SIMPLE SUPPORT CANTILEVER

OVERHANGING CONTINUOUS

IN FORMING AND BRACING DESIGN MANY OF THE MEMBERS HAVE MULTIPLE SUPPORTS. WHAT IS THE DIFFERENCE BETWEEN A CONTINOUS MEMBER AND A SIMPLE SPAN?? ASSUME A SPAN OF 10 FT. AT 1K/FT:

SIMPLE SPAN SOLUTION

CONTINUOUS BEAMS - THREE SPANS

CONTINUOUS SPAN SOLUTION

CONCLUSION: NOTE: CONTINUOUS SPAN SOLUTION HAS 10% MORE LOAD ON THE INTERIOR SUPPORTS AND 20% LESS ON THE EXTERIOR WHEREAS THE CONTINOUS IS ALLTHE SAME SHEAR IS GREATER IN THE CONTINUOUS SPAN SOLUTION 6K > 5K MAX MOMENT IS GREATER IN THE SIMPLE SPAN SOLUTION 12.5K-FT > 10K-FT

CONCLUSION CONTINUED: WOOD MEMBERS WOULD HAVE TO BE THE LENGTH OF THE FULL MEMBER BECAUSE IT IS DIFFICULT TO SPLICE EFFECTIVELY TO ACHIEVE CONTINUITY!! STEEL MEMBERS WOULD HAVE TO BE THE LENGTH OF THE FULL MEMBER BECAUSE YOU CAN SPLICE BUT WELDS AND BOLTS ARE NOT SUFFICIENT ENOUGH!!