Cấu trúc thiết bị để tiến hành các lực lượng từ những điểm mà họ bắt nguồn từ trong các tòa nhà cho các cơ sở nơi họ cuối cùng chống lại. Chúng chứa các hệ thống lực lượng đang ở trong một trạng thái cân bằng tĩnh. Đánh giá cao của các khái niệm về lực lượng, cân bằng và các thuộc tính cơ bản của hệ thống lực lượng là nền tảng cho sự hiểu biết về cấu trúc. độ lớn (Hình ). Khi hai hoặc nhiều lực lượng nonparallel cùng nhau hành động, hiệu ứng kết hợp. | Appendix 1 Simple two-dimensional force systems and static equilibrium Introduction Structures are devices for conducting forces from the points where they originate in buildings to foundations where they are ultimately resisted. They contain force systems which are in a state of static equilibrium. An appreciation of the concepts of force equilibrium and the elementary properties of force systems is therefore fundamental to the understanding of structures. Force vectors and resultants Force is a vector quantity which means that both its magnitude and its direction must be specified in order to describe it fully. It can be represented graphically by a line called a vector which is drawn parallel to its direction and whose length is proportional to its magnitude Fig. . When two or more nonparallel forces act together their combined effect is equivalent to that of a single force which is called the resultant of the original forces. The magnitude and direction of the resultant can be found graphically by vector addition in a triangle of forces or a polygon of forces Fig. . In this type of addition the resultant is always represented in both magnitude and direction by the line which is required to close the triangle of forces or polygon of forces . Fig. Force is a vector quantity and can be represented by a line whose length is proportional to its direction and whose direction is parallel to its direction. Fig. Vector addition the triangle and polygon of forces. a A body acted upon by two forces. b Vector addition produces a triangle of forces which yields the resultant. c The resultant has the same effect on the body as the original forces and is therefore exactly equivalent to them. d A body acted upon by three forces. e Vector addition produces a polygon of forces which yields the resultant. f The resultant has the same effect on the body as the original group of forces. 128 Appendix 1 Simple two-dimensional force systems and static .
