Металлические конструкции рабочей площадки

Министерство  образования и науки Украины 

Приднепровская  Государственная Академия Строительства  и Архитектуры 
 
 

Кафедра металлических и деревянных конструкций 
 
 
 
 

Расчетно-пояснительная  записка №1

«Металлические  конструкции рабочей площадки» 
 
 
 
 
 
 
 
 
 

Выполнил:                                                               ст.502 гр. Сюткин С.С. 
 

Проверил:                              Кузенко     
 
 
 
 
 
 
 

Днепропетровск 2010г.

         

             Исходные  данные:

                                                                                                    L=12м, B=6м, n=4, P=18  

                                                                                                    Материал конструкции: С225. 

                                                                                                    Класс бетона: 

                                                                                                    а=L/n=12/4=3м. 
 
 
 
 

       Расчет  второстепенной балки

       Табл. 50 СНИПа 11-23-81* 

       Принимаем балки относящиеся к І группе строительных конструкций. 

       Материал  балок – С255. 

       Табл. 51 СНИПа  11-23-81* 

       Нормативное сопротивление стали С255 при толщине  проката 10-20мм:

       Ry=240 МПа. 

       Сбор  нагрузок на второстепенную балку

       Собственный вес, вес настила, временная полезная нагрузка. 

         

       Придельная  расчетная нагрузка на второстепенную балку: 

         

       1,04 – коэффициент учитывающий собственный  вес балки. 

       Второстепенная  балка рассчитывается как изгибаемый элемент 

         

         

         
 

 
 
 

Эпюра изгибающих моментов 
 

       С – коэффициент учитывающий пластичные деформации = 1,12.

       γс=1;  γn=0,95.

       Второстепенную  балку принимаем: №45Б1 с Wx=1110см³,

                                                    А=74,6см²,

                                                     Jх=24690см . 

       Расчет  второстепенной балки на жесткость.

       Расчетный прогиб балки: 

         

       qe – эксплуатационная  нагрузка. 

         

         

       Предельно допустимый прогиб для пролета 6м: 

         

       f=0,011м<[f]=0.03м. 

       Условие выполняется – балка подобрана верно. 
 
 
 
 
 
 

       Расчет  и подбор сечения  главной балки 

       Длина главной балки L=12м. 
 
 
 
 

       

         

         

         

         
 

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            

       Минимальная высота поперечного сечения: 

         
 
 
 
 

       Площадь сечения стенки балки: 

       Минимальную площадь стенки балки определяем из условия на срез. 

         

       α ¹- коэффициент собственного веса   1,03.

       γ=1.

       Rs – расчетное сопротивление на срез. 

            

         

         

       Принимаем высоту стенки 106мм. 

         

       Условие выполняется – стенка подобрана верно. 

       Площадь сечения поясов балки 

         

         

         

         

         

       Принятое  сечение балки:

       360 х 30

       1060 х 12

       Общая высота балки:     

       Принимаем этажное сопряжение балок. 
 
 

       Проверка  главной балки на прочность: 

         

         

       Wx=13583см³. 

         

       Условие выполняется – сечение подобрано верно. 
 

       Проектирование  ребер жесткости. Их расстановка. Проверка на прочность. 
 
 

       Ребра жесткости устанавливаются под  нагрузкой. 
 
 
 
 
 
 
 
 

         

       

       

         

       Проверка  стенки на устойчивость: 

         

       Определение нормальных напряжений: 
 

       

         

         

       Определение критических нормальных и касательных  напряжений: 

         

        - табл. №21 СНИПа, зависит от  . 

        - условная гибкость стенки: 

         

         

        - по табл. № 22 СНИПа. Для  балок кроме как не подкрановой  – при непрерывном опирании  плит  = , для других случаев =0,8. 

       

        - отношение большей стороны  панели к меньшей. 

         

        - эффективная гибкость стенки. 

         

         

       Условие выполняется – ребра подобраны верно. 
 
 
 
 

       Подборка  и расчет сварных  швов главной балки

         

     между поясом и стенкой.

       Сдвигающее усилие на единицу Поясные швы в балках рассчитываются на сдвигающие усилия длины называется поперечной силой и рассчитывается по формуле:

         

  - поперечная сила.

        - статический момент пояса  балки относительно нейтральной  оси.

        -момент инерции всей балки.

       

         

       

       

       Катет шва рассчитывается по формуле:

       

 

        - коэффициент для расчета углового шва по металлу. Для автосварки =1,1.

        - расчетное сопротивление шва  на срез (табл. №56 СНиП) зависит от  электрода (табл.№55 – зависит  от метала). Для С225 – электрод  Э46А, =200МПа.

        =1 - коэффициент условий работы  метала шва.

        =1 - коэффициент условий работы.

       

       По  табл. 38 СНиПа принимаем =6мм. 
 

       Расчет  опорного ребра:

       Нагрузка  с балок на опоры передается через  опорные ребра:

       Толщина ребра:

       

        - расчетное сопротивление смятию  торцевых поверхностей при наличии подгонки: =346МПа.

        =360мм – ширина ребра.

       

       Проверяем устойчивость опорной части балки:

       

       Площадь опорной части балки:

       

       

       Гибкость  опорной стойки:

              - коэффициент продольного изгиба.

       Проверяем устойчивость опорной части балки:

       

         
 
 
 
 
 
 
 
 
 
 
 
 
 
 

       Подбор  сечения колонны:

       

        Расчетная схема:    

              .

                
                                                                

                                                         

                                                          

                                                            Для несущих сжатых элементов  .

                   Принимаем , .