Relating to the above, the two recently published papers for BEI 2024 listed below have information on the use of strengths for bridge assessments. They are accessible using the link below.
Wong and Vimonsatit (2024), "Determination of MCFT-Based Shear Strength for Shear Load Rating of
Concrete...
...sign ">=" in the equation for the required tension force. Similarly, for section shear requirement for adequacy in AS 5100.5, the equation φVu >= V* where Vu =Vus + Vuc is not derived from considering forces using an equilibrium diagram; it is from a resistance model.
The magnitude of the...
...AASHTO codes all have a different set of equations from that of AS 5100.5. AS 5100.5 has no restriction, AS 3600 with Admt 2 restricts φVus to V*-φVuc and both AASHTO and Canadian Codes restrict φVus to not greater than V*. Owing to this, determining the degree of adequacy across these...
The attachment for the WXMAXIMA check is provided here.https://files.engineering.com/getfile.aspx?folder=8c899bb1-4484-4e47-8fd6-032b407dbdb5&file=20231104_-_Case_2_with_N10_ligature_check_using_wxmaxima.pdf
The attachment for M*=400 kNm is provided here.https://files.engineering.com/getfile.aspx?folder=e30d89ca-bd21-4ea6-b460-614e4d393933&file=20231104__5100.5_section_design_check__using_excel_for_M_design_of_400_kNm.pdf
The attachment for M*=297 kNm is provided here as I have problem when editing the above post to include this attachment.https://files.engineering.com/getfile.aspx?folder=0c80891a-d6a7-4247-a869-05b62b3f8367&file=20231104__5100.5_section_design_check__using_excel_for_M_design_of_297_kNm.pdf
...They are still basically the same as my previous findings except incorrect values have been corrected. Also two excel files are attached, one for M*= 297 kNm and another for M*=400 kNm (in response to IDS comment number 1). Also an independent check using the open software WXMAXIMA has been...
...gives bending capacity results that are highly unconservative"
As shown from the result of my excel attachment, for a set of load effects M* and V*, increasing the area required for the design loading has no effect on the bending moment. As described earlier, the resulting design is more...
...below.
While both codes allow the calculated mid-level strain (my value is 8.967E-4) to be increased up to 0.003 from the value calculated for M* and V* (my values are M* = 258 kNm and V* =275 kN) for calculating Θv and kv (which is conservative for both load-rating and and design since the...
...since I did not adjust the mid-depth strain. The strain used for my calculation of φVu is equal to the strain calculated using the load effects of M* = 258 kNm and V* = 275 kN. To ensure consistency between the shear strength and the corresponding load effects (a key feature of MCFT),the...
...Institute of Australia Conference Concrete2023 held in Perth 10-13 September 2023, stated that:
(1) the equation in Amendment 2 to limit phiVus = V* -phiVuc is not necessary as the amount of longitudinal steel determined in the old version is adequate to resist V*.
(2) Clause 8.2.7 AS 3600...
Doug,
If you refer back to your earlier posting dated 21 Sep 23 (see above quote) and go through my previous postings on https://www.eng-tips.com/viewthread.cfm?qid=499791, you will notice that I did not ignore the missing restriction in the AS 5100.5 equation. The paper presented at the...
Rapt,
The equation for additional force with the term φVus in longitudinal steel caused by shear in Clause 8.2.7 of AS 3600-2018 with Amdt 1 and AS 5100.5-2017 with Amdt 1 is not based on MCFT. This can be seen in previous published papers mentioning this equation.
In the paper "Background to...
Bugbus,
If you iterate using the live load portion V*(LL) only and match the varying V*(DL+LL) with Vu to give Vu(iteration), the factor determined using V*(DL&LL) (design shear), Vu(iteration) [Use this Vu to replace phiVu in the load rating equation] and V*(DL) is a scaling factor. This...
Bugbus,
My post above is consistent with how we do design now. For a set of (V_d*,M_d*) calculate V_ud, so this Vu_d is consistent with M_d*/_dV*. check whether V_d*=phiV_ud if we want optimal adequacy. So we have consistency since M_d*,V_d* and phiV_ud is for the same level of loading.
I am...
If you iterate using the live load portion V*(LL) only and match the varying V*(DL+LL) with phiVu to give phiVu(iteration), the factor determined using V*(DL&LL) (design shear), phiVu(iteration) and V*(DL) is a scaling factor. This factor applied to the full vehicle gives a scaled vehicle with...
The figure of the block shown in the Concrete2023 conference (reference given above) by Vimonsatit, Wong and Mendis (2023) is reproduced below. Note the typo error - label Vp should read Pv.
Suggest you get hold of a recent copy of AASHTO bridge Specification to view the diagram and the assumptions made, and to see the equation is derived. In AASHTO 2010 5th Edition, this diagram has a label "Forces Assumed in Resistance Model Caused by Moment and Shear". An assumption is made that...
...Doug,
Thank you for your comments.
I agree with including a restriction "The term phiVus should not be taken to be greater than V*" . Designers can still use phiVus > V* for section shear design.
This should be changed to using phiVus to be consistent with the equations in other national...
