Thanks. Yes, the code language regarding Alterations, which is what this is, says, "Portions of the structure not altered and not affected by the alteration are not required to comply with the code requirements for a new structure". As I read this though it seems that since the existing roof...
Yes, ground snow loads here in MD are higher now. The skylights will project around 18" above the roof slab, plus there are a number of penthouses up there too, so it's not a case of a simple flat roof. I was leaning in the direction of saying the new code will apply. I'll run the numbers and...
I've been asked to evaluate an existing flat roof structure (reinforced concrete) of a building built in the 1970's for the installation of replacement skylights. The new skylights that the owner wants are double glazed and between that, the new flashing needed, and a canopy shading mechanism...
Does anyone have any experience in determining the load bearing capacity or acceptable live loads for an existing raised access flooring system of the kind you often find in computer rooms. The system in question is made of 24" square removable floor panels (which are probably made of a wood...
A question has come up about existing floor load capacity in a library. It was designed and built in the early 1970's, and I have the drawings (architectural and structural) which show it as three stories, basically reinforced concrete on spread footings. The problem is that the middle floor...
I was wondering the same kinds of things myself when I heard about these failures. My suspicion is that these collapses were probably due to a combination of extreme loading conditions especially in some localized spots, poor or incomplete structural detailing, maybe a construction error or...
Appendix B (Steel Embedments) of ACI 349-97 is a method for determining anchor bolt pullout strength. I think this appendix is now part of the latest ACI 318 design guide. It is based on a simple formula for the shear strength of the concrete times the surface projected area of a stress cone...
Thanks for the comments. Has anyone had any experience with or knowledge of someone sending out drawings or design calcs to an outside firm for the purposes of review and QA? What do you think of this idea? And what would you think of the idea of sending out a set of drawings and supporting...
A question has come up about what is 'typical' in the industry regarding Civil/Structural and other engineering discipline internal reviews of designs. In my former days with Bechtel every set of design calculations and sketches was checked by another engineer within the group and signed off...