Karl Hoitsma, P.E.
Structural Engineer
Tyler, TX

I am available and ready to do consulting work for other engineers.

• Industrial,
• Institutional,
• Commercial, or
• Research

For instance, happy to assist with review, checking, calculations, or programming.

Typically available on short notice, tight deadlines, willing to work off-shift β nights, weekends.

Email: khoitsma at mathpax.com

Search the blog by subject matter:Β Tabular List β Blog Entry Search

Extensive experience in programming suited to engineering work — examples follow:

 STRUCTURAL ENGINEERING LINK DISCUSSION ASCE Exact Wind Integration (closed form equations) Developed single function to calculate all aspects of ASCE wind design: force moment diagonal tributary elements allowed horizontal offset basis elevation basis Multi-Page Apps using Dash/PythonAnywhere Apr2020 (updated May 2024) Developed working online apps for structural design: Grating β online design spreadsheet Beams β strong axis bending, any Cb Shapes β filtered, sorted Shapes β properties WT eccentric braces β with plot WT eccentric braces β with two plotsEnhanced β calculates smallest, lightest shapes, and capacities Bolt groups β coefficient C, with plot Bolt shear β configuration capacity WT Braces Mar 2020 Developed design basis for eccentrically loaded WT brace members, allows comparison with concentric braces Single angle braces vs WT braces Feb 2020 I compare the simplicity and efficiency of single angles to WT braces Calculate Beta w for Single Angles Dec 2019 The beta value for single angles is an elusive parameter.Β  I developed a closed form solution for the beta value. AISC Bolt Shear β C Coefficient Jul 2019 Here is my iPhone app for determining bolt group coefficients β with plots. See video. ASCE 7-16 Kzt Calculation β with Chart Jul 2019 Here is my iPhone app for determining the ASCE Kzt parameter. See video. AISC Bolt Shear (with video) Jun 2019 AISC Bolt Shear Capacity β Improved UI Jun 2019 AISC Bolt Shear Capacity β Online app (C1) developed May 2024 Here is my iPhone app for determining the allowable bolt shear in accordance with AISC. Beautiful, very quick to use. Bromβs Method Sep 2017 Rigid shaft foundation design ASCE 7-16 Ice Loading Apr 2018 Developed function,Β get_iceweight() for any structural shape pipe, HSS, bar L, 2L, 2L spaced C, MC W, S, M, HP WT, ST, MT Wind and Fire-proofing Dec 2017 Explicit wind calculation for steel members including fireproofed beams and columns. MATHEMATICS I coded a PyXLL macro that builds a multi-dimension data table. The native Data Table provided by Excel is useful but limited to two variables. My version is set up for 5 dependent variables and an unlimited (theoretically) number of dependent variables. I built an Excel dropdown function β that requires no worksheet reference! Reasoning The dropdown built into Excel requires a range of data to populate the dropdown list. This might be an appropriate situation if the spreadsheet is a one-off. In my work, the dropdown list would more appropriately be generated in my PyXLL program. Having the dropdown and its data provided by a PyXLL function allows: central control of the list easy updating unrestricted placement of the dropdown β any spreadsheet, any tab, any cell I built an Excel FIS Calculator Features easy fraction entry general triangle solutions similar triangle solutions
Email: khoitsma at mathpax.com

DISCLAIMER

Reference on this website to any specific commercial products, process, service, manufacturer, company, or trademark does not constitute its endorsement or recommendation by Karl Hoitsma.

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This last section on this page is a toy app that I built using Observable. The user can select from 3 AISC shapes — C, S, and W. The two charts illustrate the AISC sections that have an integer depth (in inches). The first chart lists the smallest weight sections with integer depth; the second chart lists the largest weight sections with integer depth. The abscissa (domain) is limited to 200 pounds per foot. Again, just a toy.