## ASCE 7-10

## ASCE 7-10

(OP)

I would like to use combination in section C2.3.5 i.e. 1.2D+1.6L+1.0T. I do not know what resistance factor for design strength should be used. I have spatial stress state (not only tension, compression, shear separately).

What value should be multiplied Nominal Strength to get Design Strength?

What value should be multiplied Nominal Strength to get Design Strength?

## RE: ASCE 7-10

## RE: ASCE 7-10

## RE: ASCE 7-10

For AISC based design (buildings) the resistance factor would be based on considerations of the material type and the member/element type.

For spatial stress checks - if buckling and second order effects are dealt with, then based on that particular steel (that has a fairly good ductility) I would guess a Φ = 0.9 as the resistance factor would only consider variations on material properties.

Variations in other parameters that drive a particular Φ level, such as variations in dimensions, thicknesses, warping, etc. would not enter into the stress check you seem to be doing (Von Mises?).

## RE: ASCE 7-10

## RE: ASCE 7-10

Acc. to ASCE7-10, C2.3.5 for self-straining loads below combinations should be used:

1.2D + 1.2T + 0.5L

1.2D + 1.6L + 1.0T

It seems to be LRFD. LRFD use force and moments capacity. How to relate it to my spatial stress state? How to calculate design strength?## RE: ASCE 7-10

Is this a building? A pressure vessel? A catwalk? What is it?

There should be a governing code or specification that would provide design criteria for you to use.

The ASME pressure vessel code link - http://www.asme.org/kb/standards/bpvc-resources/bo...

(The link I posted earlier above is wrong for some reason.)

## RE: ASCE 7-10

## RE: ASCE 7-10

What reference or standard is used to determine the allowable stress for ASD design of the hopper?

For example, structural steel for buildings in the USA is designed with AISC's Specification for Structural Steel Buildings, AISC 360. This current specifcation includes the saftey factors for ASD and the Resistance Factors, Φ, for LRFD. There is not one Φ factor for everything. Shear, bending and weld strength may all have different Φ factors. When checking tension there are two differnt Φ factors: one for yielding of the gross secion and another for rupture of the net section (eg. net section where bolt holes occur and yieliding is not a concern).

## RE: ASCE 7-10

## RE: ASCE 7-10

OK, maybe auxiliary question, which help focus on the point of subject:

In attachment there is a screenshot from book "The structural design of air ducts and gas ducts" (5.1.1, 5.1.2,5.1.3,5.4.6). Section C2.4.4 is from ASCE7-10. There is mentioned about "normal allowables stress". From point 5.1.1 it can be concluded that "normal allowable stress" concerns not only normal stress

(i.e. not only tension/ compression but also shear and bending)? So this normal allowable stress can be used in Combined Stress State like in my analysis? How to determine this "normal allowable stress"?

## RE: ASCE 7-10

## RE: ASCE 7-10

howto design it? Why don't you ask a supervisor?Before you doing anything creative, make sure the code likes the artwork you are trying to wow the world with.