Five types of primary structures

Tension structures1.Compression Structures2.Trusses3.Shear structures4.Bending structures5.

Real trusses connects members using "gusset plates" -Kassamali

"A structure refers to a system of connected parts used to support a load. Important examples related to civil engineering include buildings, bridges, and towers; and in other branches of engineering, ship and aircraft frames, tanks, pressure vessels, mechanical systems, and electrical supporting structures are important." - Hibbele

Imagine a view without the bridge

The pedestrian bridge suppose to be

Safe1.Aesthetically pleasing2.Serviceable - makes sense from the world, stays within the sound usable state (balance is criticized)

3.

Also, you will considerEconomic factor4.Environmental considerations ( glass brick is criticized)5.

(Zubizuri bridge, Bilbao, Spain)

Loads on Structures

Dead Loads1.Live loads / Action loads2.Wind loads3.Snow loads4.Bridge loads (also action loads)5.Impact loads6.Earthquake loads7.

Eurocode I

Lectures_ Week 107 January 2014

16:57

Loads on Structures_Lecture 1_3 Page 1

Eurocode I

Reference Title

BS EN 1991-1-1 Densities, self-weight and imposed loads

BS EN 1991-1-2 Actions on structures exposed to fire

BS EN 1991-1-3 Snow loads

BS EN 1991-1-4 Wind actions

BS EN 1991-1-5 Thermal actions

BS EN 1991-1-6 Actions during execution

BS EN 1991-1-7 Accidental actions due to impact and explosions

BS EN 1991-2 Traffic loads on bridges

BS EN 1-3 Actions induced by cranes and machinery

BS EN 1-4 Actions in silos and tanks

Reference

Australian code: AS/NZS 1170

Problems! (Hibbeler, 2012)

A two-story office building shown in the photo has interior

columns that are spaced 22m apart in two perpendicular directions. If the (flat) roof loading is 2kN/m2 determine the live

load supported by a typical interior column located at ground level (assume action load for office building is 3kN/m2).

Find the components of the force F in the directions of Ox

and Oy shown in Figure.

The floor system of a gymnasium consists of a 130-mm-thick

concrete slab resting on four steel beams (A = 9,100 mm2), that, in turn, are supported by two steel girders (A= 25,600

mm2), as shown in Fig.3. Determine the dead loads acting on beam BF and girder AD. (Assume steel density of 7.8g/cm3)

Loads on Structures_Lecture 1_3 Page 2

Note: Eurocode increased bulk density of concrete from 2.4g/m3 to 2.5 g/m3

Statically determinate and indeterminate

Determinate structure means it can be solved by equilibrium equations

Determinacy or indeterminacy of a structure can be external or internal

total number of support reactions > number of equilibrium equations.External indeterminacy:

total number of unknown member forces > number of the equilibrium equations (when look at the relevant internal FBD)

Internal indeterminacy

m + r = 2j or m = 2j - r determinatem + r > 2j or m > 2j r indeterminatem + r < 2j or m < 2j r unstable

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