What's New in CONNECT Edition V9.6
This document describes new or enhanced features of STAAD Foundation Advanced (SFA) since the CONNECT Edition V9.5 (Release 9.5.0.62).
Major Enhancements
1. The 2019 edition of the Canadian concrete code A23.3 is now available for isolated footings in SFA’s General & Toolkit modes.
Salient features
The footing(s) can be designed to service and ultimate load cases/combinations which are created within the SFA environment, as well as to those imported from a STAAD.Pro superstructure model.
From the standpoint of the size of the footing, two types of design are available.
Load combinations can be generated to the 2005 edition of the NBCC code within the SFA environment provided that the column reaction loads for primary load cases, categorized as Dead, Live, Wind, Seismic, etc., have been specified or have been imported from the STAAD.Pro model. Alternatively, the combinations can be specified in the STAAD.Pro superstructure model and, after the analysis of that model, the support reactions for those combination cases can be imported into SFA for the service and ultimate checks.
In both modes – General and Toolkit – from the standpoint of load cases and/or combinations, the minimum that needs to be present is either A or B, where,
A: One primary load case
B: One service load case/combination, and, one ultimate load case/combination
Checks performed for service load cases/combinations
Items 2, 3and 4are multiplied with the factors specified in the “Selfweight and Deadweight Factor table” corresponding to the load case being designed.
Checks performed for ultimate load cases/combinations
After the service level checks described above are computed and the footing is found to be safe for all those checks, the soil pressures are calculated for the ultimate load cases/combinations. Following this, the program calculates the bending moments, oneway and twoway shear forces which are then used in the following checks.
The above-mentioned checks are generally similar to the ones performed for other codes such as ACI 318. The following table shows the list of the equations and sections of the Canadian code that are used in the concrete design checks for the ultimate load cases.
Description
Section of the A23.3-2019 code
Minimum thickness of the footing
13.2.1, 13.2.3, 15.7
Effective depth for oneway shear
3.2 (Symbols)
Effective depth for twoway shear
13.3.1.2
Neutral Axis factor β_{1}
Equation 10.2, section 10.1.7 (c)
Concrete Strength Factor α_{1}
Equation 10.1, section 10.1.7 (c)
Concrete Density Factor λ
8.6.5.a (Normal density concrete assumed)
Maximum Concrete Strain
10.1.3
Concrete Stress Distribution
10.1.7
Neutral Axis Depth & Ductility clause
10.5.2
Resistance Factor for concrete φc
8.4.2
Resistance Factor for reinforcement φs
8.4.3
Compressive & Tensile strengths of concrete
Maximum yield strength of reinforcement
8.5.1
Stress-strain curve for concrete & steel
8.5.3.2
Modulus of elasticity of steel
8.5.4
Lower & Upper limits for concrete strength
8.6.1.1
Minimum reinforcement for flexure
Smaller of (7.8.1, 10.5.1.1)
Cracking Moment & Modulus of rupture
8.6.4
Factored Shear Resistance of Concrete
Equation 11.6, section 11.3.4
Maximum Factored Shear Resistance of concrete
Equation 11.5, section 11.3.3
Effective web width for shear capacity calc
11.2.10.1
Shear capacity factor β
11.3.6.3(b), 11.3.6.3(c)
Maximum size of coarse aggregate for β calculation
20 mm (assumed), 11.3.6.3(b)
Critical location for oneway shear
11.3.2
Critical location for twoway shear
13.3.3.1
Factored punching shear stress resistance
Equations 13.5, 13.6, 13.7, section 13.3.4.1
Reduction in effective depth for punching
13.3.4.3
Unbalanced moment (UBM) effects
13.3.5.3, 13.3.5.4 and 13.3.5.5
“J” and other terms in UBM effects
Section 8.4.4.2.3 – ACI 318-2014
Concrete Bearing Check
10.8.1
Development Length calculation
12.2.3, 12.11.3
Output from the program
The following results are available for viewing through the program’s calculation reports.
2. The 2019 edition of the Canadian concrete code A23.3 is now available for mat foundations in SFA’s General mode.
Mats too are designed to service and ultimate load cases/combinations which are created within the SFA environment, as well as to those imported from a STAAD.Pro superstructure model. The workflow is as follows.
Either
or
Notes:
Design for flexure:
Design for oneway shear
Design for twoway (punching) shear
Design for the pile punching through the mat.
Output from the program consists of
a) Summary of minimum/maximum nodal displacements from the FE model
b) Summary of minimum/maximum plate element stresses and moments from the FE model
c) Summary of maximum soil pressures from the various service load cases/combinations.
d) Contact Area report for each service load case/combination. A loss of contact will be evident through a value that is less than 100%
e) Report of Sliding and overturning check for each service load case/combination.
f) Static equilibrium mismatch report in the event of instabilities that cause overturning or sliding.
g) Pile reaction summary for service and ultimate load cases/combinations.
h) Details of the flexure design checks for the longitudinal and transverse directions for top and bottom surfaces.
3. Design of pedestals on mats and isolated footings designed to the Canadian code
For the aforementioned isolated footings and mats which are designed to the A23.3 2019 Canadian code, SFA can perform the design of pedestals as a short column for the axial force + biaxial bending moments for each ultimate load case/combination that is included in the job. But, this design is presently done to the ACI metric code using the ACI Metric bar database. This is expected to be modified in a future release by enabling design to the Canadian A23.3-2019 code.
4. Punching shear check for foundations for the Indian code
For isolated footings, combined footings and mats designed to the Indian code, the punching shear check has been enhanced to include the unbalanced moment effects per section 31.6.2.2 of the code. This has also been done for octagonal footings resting on soil supporting a vertical vessel.
Defects rectified