A presentation that explains the various systems and techniques of employing steel and concrete to support long span structures. The range varies from conventional beams, to trusses and portal frames.
In a group of 6, we are required to select the design of the members in studio 3. In a group, we are to redesign the roof of the building by using truss design.
A presentation that explains the various systems and techniques of employing steel and concrete to support long span structures. The range varies from conventional beams, to trusses and portal frames.
In a group of 6, we are required to select the design of the members in studio 3. In a group, we are to redesign the roof of the building by using truss design.
Design and analysis of stress ribbon bridgeseSAT Journals
Abstract
A stressed ribbon bridge (also known as stress-ribbon bridge or catenary bridge) is primarily a structure under tension. The tension cables form the part of the deck which follows an inverted catenary between supports. The ribbon is stressed such that it is in compression, thereby increasing the rigidity of the structure where as a suspension spans tend to sway and bounce. Such bridges are typically made RCC structures with tension cables to support them. Such bridges are generally not designed for vehicular traffic but where it is essential, additional rigidity is essential to avoid the failure of the structure in bending. A stress ribbon bridge of 45 meter span is modelled and analyzed using ANSYS version 12. For simplicity in importing civil materials and civil cross sections, CivilFEM version 12 add-on of ANSYS was used. A 3D model of the whole structure was developed and analyzed and according to the analysis results, the design was performed manually.
Keywords: Stress Ribbon, Precast Segments, Prestressing, Dynamic Analysis, Pedestrian Excitation.
Design and analysis of stress ribbon bridgeseSAT Journals
Abstract
A stressed ribbon bridge (also known as stress-ribbon bridge or catenary bridge) is primarily a structure under tension. The tension cables form the part of the deck which follows an inverted catenary between supports. The ribbon is stressed such that it is in compression, thereby increasing the rigidity of the structure where as a suspension spans tend to sway and bounce. Such bridges are typically made RCC structures with tension cables to support them. Such bridges are generally not designed for vehicular traffic but where it is essential, additional rigidity is essential to avoid the failure of the structure in bending. A stress ribbon bridge of 45 meter span is modelled and analyzed using ANSYS version 12. For simplicity in importing civil materials and civil cross sections, CivilFEM version 12 add-on of ANSYS was used. A 3D model of the whole structure was developed and analyzed and according to the analysis results, the design was performed manually.
Keywords: Stress Ribbon, Precast Segments, Prestressing, Dynamic Analysis, Pedestrian Excitation.
An academic presentation that highlights main shafts applications and conduct stress and fatigue analysis in shafts as shafts being an essential part in the automotive manufacturing
This lifting machine is used to carry heavy industrial machinery like lathe from one floor to another. We have analysed the strength and the capacity of this machine. We have checked critical points for failure and suggested design recommendations to increase the capacity to 3 tonnes from the present value of 1.1 tonne.
Team members: Ahsen, Ankit, Ankit, Shivam, Anurag, Deepak
This is a power point presentation on the design of Helical springs subjected to Static and Fluctuating load. It is part of Design of Machine elements subject.
4. Synchrotron Project
• The structure consists of main three-dimensional spine truss and Ratt type
secondary trusses of 1.50m module to receive the roof purlins at the same
locations at 7.5m bays.
• The building is of 60x60m dimensions resting on reinforced concrete column
framing.
• All trusses are to be free in horizontal movement to prevent any secondary
trusses being developed by thermal or any other secondary effects.
• The buildings is to be equipped with an electrical over-head 10.0-ton crane
resting on 3-rails, one at either one of two alternative location on the spine truss
and the remote ends on concrete corbels to be cast as part of the concrete
columns.
5.
6. Loads
• DL: Dead load is estimated as self-weight.
• SL: Snow load as alternate to the (Live Load) has been specified at
175kg/m2 (1.75kN/m2) for increased safety due to the importance of the
structure.
• CL: Crane load is taken as 10.0-ton (100kN) Payload capacity.
9. Analysis Procedure
• First of all, analysis of the secondary trusses was applied (secondary
trusses were taken as separated units considering connections with the
main truss are supports i.e. without the effect of the main truss); in order
to transfer forces from secondary trusses to the main truss through
connections (forces here are the external forces supported by these trusses
and members’ own weights). Action and reaction principle is applied.
• Through the analysis of the secondary trusses the following is applied:
1. Reactions were calculated by assuming sections for truss members and
sections for the purlins above (sections are assumed compared to the
previous design), in addition to the external loads (snow load) which are
considered as the loads that are supported by the columns (supports).
2. Members weights were transferred equally (1/2 of member weight.) to
each joints holding every member.
10. Analysis Procedure
3. Loads were multiplied by factors in order to achieve the ultimate
design loads (1.6 L.L and 1.2 D.L).
4. Reactions were calculated using structural analysis methods.
5. Connections between main and secondary trusses were considered to
be reactions.
• After the analysis of the secondary trusses was completed, analysis of the
main truss was performed considering instead-of-connections forces to be
the main forces affecting the main truss.
• Reactions must be calculated first to begin the analysis of the main truss
(using structural analysis methods). Here a computer program was used
to calculate them (Staad Pro software).
13. Design Procedure
Design of Tension Members:
• The selection of members to support given tension loads is described. Although the
designer has considerable freedom in the selection the resulting members should
have the following properties:
1. Compactness.
2. Dimensions that fit into the structure with reasonable relation to the
dimensions of the other member of the structure.
3. Connections to as many parts of sections as possible to minimize shear lag.
• The type of connections used for the structure often affects the choice of member
type. Some steel section are not very convenient to bolt together with the required
gusset or connection plates, while the same section may be welded together with
little difficulty. Tension members consisting of angles, channels, and W and S
section will probably be used when the connections are made with bolts, while
plates channels, and structural tees might be used for welded structures.
14. Design Procedure
Design of Tension Members:
• The slenderness ratio of a member is the ratio of its unsupported length to its
least radius of gyration. Steel specifications give preferable maximum values of
slenderness ratios for both tension and compression members. The purpose of such
limitations for tension members is to ensure the use of section with stiffness
sufficient to prevent undesirable lateral deflection or vibrations. Although tension
members are not subject to buckling under normal loads, stress reversal may
occur during shipping and erection and perhaps due to wind or earthquake loads.
Specifications usually recommend that slenderness ratios be kept below certain
maximum values in order that some minimum compressive strengths be provided
in the members. For tension members other than rods, the ASIC Specification does
not provide a maximum slenderness ratio for tension members, but Section D.1 of
the specification suggests that a maximum value of 300 be used.
15. Design Procedure
Design of Compression Members:
• The designs of several axially columns are presented. Included are the selections
of single shapes, W sections with cover plates, and built-up sections constructed
with channels. Also included are the designs of sections whose unbraced lengths in
the x and y directions are different, as well as the sizing of lacing and tie plates for
built-up sections with open sides. Another topic that is introduced is flexural
torsional buckling of sections.
• The design of columns by formulas involves a trial-and-error process. The LRFD
design stress ɸ F and the ASD allowable stress F/Ω are not known until a column
size is selected, and vice versa. A column size may be assumed, the R-values for
that section obtained from the Manual or calculated, and the design stress found
by substituting into the appropriate column formula. It may then be necessary to
try a larger or smaller section.
20. Connection Procedure
• There are, in general, two types of connections, one is bearing type connection and
the second is slip critical connection.
• The design of a connection means both, to determine the number of bolts in that
connection and to determine the spacing between those bolts (bolt-to-bolt spacing
and edge spacing).
• To determine the number of bolts, one must first assume the diameter and the
type of bolts to be used.
• Based on the diameter and the type of bolts, the capacity of each bolt can be
determined in each shear, tension, and slipping.
• After that, number of bolts can be determined by dividing the maximum applied
force on the least capacity of the bolt i.e. shear, tension, and slipping capacities.
21. Connection Procedure
• When the number of the bolts is determined, the spacing can be determined based
on bearing capacity i.e. by choosing edge and bolt-to-bolt spacing to be between the
minimum and maximum spacing, then checking if those spacing will give the
required capacity to support the entire maximum applied load.
Minimum edge spacing Le-min (table J3-4 AISC code).
Maximum edge spacing Le-max = 12t or 6 inches whichever is less.
Minimum bolt-bolt spacing Smin = 2.667d but 3d is preferable
Maximum bolt-bolt spacing Smax = 24t or 12 inches whichever is less. (For
protective bolts)
• Bearing capacity /bolt -------- 𝜙𝑅 𝑛 = 𝜙1.2𝐿 𝑐 𝑡𝐹𝑢 or ϕ2.4dtF_u whichever is less.
