ce- 416 truss & frame
DESCRIPTION
Name: Md. Neshar Ahmed Limon 4th year, 2nd semester ID: 10.01.03.151 Sec: C Ahsanullah University of Science & TechnologyTRANSCRIPT
![Page 1: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/1.jpg)
Presented To
Sabreena Nasrin
B.Sc. Engg. (Civil), BUET
Lecturer at Ahsanullah University of Science & Technology
&
Munshi Galib Muktadir
B.Sc. Engg. (Civil), BUET
Lecturer at Ahsanullah University of Science & Technology
Md. Neshar Ahmed
Student ID: 10.01.03.151
4th Year, 2nd semester
Department of Civil Engineering
Ahsanullah University of Science & Technology
Welcome to my Presentation on Truss & Frames
Presented By
CE-
416
![Page 2: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/2.jpg)
A truss is a structure composed of slender members joined together at their end points. Planar trusses lie in a single plane. Typically a truss is a joint framed structure which is designed to sustain inclined, vertical or horizontal loads occurring at or between its points of supports and has the following characteristics:
Truss
Typical figure of Truss & Frames
Straight Members
Members connected at their intersections by means of frictionless pins or hinges
Members so arranged that the truss is loaded only at the joints
![Page 3: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/3.jpg)
Components of Truss
![Page 4: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/4.jpg)
Pitched Truss- Characterized by its triangular shape. It is most often used for roof construction.
Parallel Chord Truss- Its named from its parallel top and bottom chords. It is often used for roof construction.
Basic Types of Truss
![Page 5: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/5.jpg)
Various Types of Truss
Flat Truss
King Post Truss
Queen Post Truss
Lenticular Truss Lattice Truss
Bowstring Truss
![Page 6: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/6.jpg)
![Page 7: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/7.jpg)
![Page 8: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/8.jpg)
![Page 9: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/9.jpg)
Calculations for AnalysisThe analysis of trusses is usually based on the following simplifying assumptions:
The centroidal axis of each member coincides with the line connecting the centers of the adjacent members and the members only carry axial force.
All members are connected only at their ends by frictionless hinges in plane trusses.
All loads and support reactions are applied only at the joints.
![Page 10: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/10.jpg)
Method of Joints
Method of Joints: The axial forces in the members of a statically determinate truss are determined by considering the equilibrium of its joints.
Tensile(T) axial member force is indicated on the joint by an arrow pulling away from the joint.
Compressive(C) axial member force is indicated by an arrow pushing toward the joint.
![Page 11: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/11.jpg)
![Page 12: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/12.jpg)
![Page 13: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/13.jpg)
![Page 14: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/14.jpg)
![Page 15: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/15.jpg)
![Page 16: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/16.jpg)
![Page 17: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/17.jpg)
Truss Design Considerations
Effect of tension vs. compression on member sizes
Potential for stress reversal
Potential buckling failure modes and approaches to preventing
Overall lateral stability (lateral- torsional buckling)
Member redundancy: Determinate vs. Indeterminate Trusses
![Page 18: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/18.jpg)
![Page 19: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/19.jpg)
![Page 20: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/20.jpg)
![Page 21: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/21.jpg)
![Page 22: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/22.jpg)
Truss Determinacy Formula
n = 2j – 3 →for determinacy
n = Number of truss bars�
j = Number of joints�
n > 2j -3 →indeterminate
n < 2j -3 →unstable
![Page 23: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/23.jpg)
Eifel Tower
Some renowned Trussed Structures
![Page 24: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/24.jpg)
Frames Multi forced members are generally known as
Frames.
Frames are commonly used to support various external loads.
Figure of Frames
![Page 25: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/25.jpg)
Advantageous features of Framed structure
1. Speedy construction due to simplicity in geometry –consist of only columns and beams (or partially by the floor slab) as the main structural elements
2. Very rigid and stable –able to resist tremendous vertical (dead load) and lateral loads (wind)
3. Reduced dead load –absent of thick shear wall etc.
4. Roofed over at an earlier stage –every floor slab being finished becomes an cover to protect the lower floors from sun and rain
5. Offer large unobstructed floor areas –without obstacle between columns
6. Flexible utilization of space
![Page 26: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/26.jpg)
Advantages features of Framed structure (continued)
7. Adaptable to almost any shape
8. Easily altered within limits of frame –regular or non-regular grid system is very adaptable in spatial arrangement
9. Offsite preparation possible –especially for prefabricated construction using pre-cast concrete or structural steel elements
10. May be designed to accommodate movement
11. Acceptable distribution of natural light –window openings can be provided easily on eternal walls
12. Easy to design structurally including computer design –again, due to simple geometry
![Page 27: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/27.jpg)
Principle factors affecting choice of frame
Structural Design consideration
Foundation consideration
Standardization of members or design
Span and floor loads
Fire resistance requirement
Maintenance consideration
Integration of architectural & structural elements
![Page 28: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/28.jpg)
Features of In-situ concrete frame construction
Construction aspects
1. In-situ concrete is inconsistent in quality in performance -mixing, delivery, placing and compacting of concrete require very tight quality control
2. Overlapping formwork, steel fixing and concreting process make site operations more difficult –these works are to be done almost at the same time at the same location
3. Formwork erection is often timely, expensive, environmental unfriendly and labour intensive
4. Increase a lot of wet-work –difficult to maintain site in a clean and tidy environment
![Page 29: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/29.jpg)
Draw the FBD of the frame or machine and its members as necessary.
Then identify any two-forced members
For a joint with more than two members or an external force, it is advisable to draw a FBD of the pin.
Analysis for Frame
![Page 30: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/30.jpg)
Some Examples Framed Structures
![Page 31: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/31.jpg)
DIFFERENCE BETWEEN TRUSSES AND FRAMES
Trusses Frames
Members are subjected to tension/compression
only
At least one member is subjected to bending,
shear or torsion
Composed of rods Composed of bars
Usually more simple to calculate, more weight
effective
Usually more simple to manufacture, and to place in tight layout
![Page 32: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/32.jpg)
DIFFERENCE BETWEEN TRUSSES AND FRAMES
Connection by riveting,
moment-resistant
![Page 33: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/33.jpg)
DIFFERENCE BETWEEN TRUSSES AND FRAMES
Connection by welding,moment-resistant
![Page 34: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/34.jpg)
Cost Effective Can be installed quickly even without heavy
equipment to lift it into place Unique properties of a triangular object allow
trusses to span across longer distances A triangular truss maintains its shape,
preventing shift and sag. Thus giving stability to the structure.
The shape of a triangle allows all of the weight applied to the sides to be redistributed down and away from the centre.
Advantages of Truss & Frames
![Page 35: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/35.jpg)
![Page 36: CE- 416 Truss & Frame](https://reader033.vdocument.in/reader033/viewer/2022061201/547a0c9eb479598a098b4918/html5/thumbnails/36.jpg)