PSI - Issue 84

Galileo Tamasi et al. / Procedia Structural Integrity 84 (2026) 709–716

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with the embankment without surcharge. Finally, the foundation piles were verified against buckling using the Caquot formula, while the lateral friction capacity was determined through the Benabenq formula. 4.4. Simulation strategy and available software routines In order to maintain historical integrity, this study avoids the creation of new software for methods such as Engesser method solution program, focusing instead on the application of existing routines developed and published during the 1970s. This approach ensures that the simulated design remains a faithful reconstruction of the computational capabilities available to engineers of that era. For the analysis of the superstructure, which consists of a symmetrical two-span continuous beam, specific pre-coded programs were selected from the standard technical libraries of the period. The computational workflow involves two main phases. First, the longitudinal response of the continuous beam is determined using algorithms dedicated to the resolution of statically indeterminate structures on the HP 67/97 platform. Subsequently, the cross-sections of the deck, specifically the rectangular and T-shaped sections of the main girders, are verified using original software routines designed for reinforced concrete member analysis. These programs allow for the direct verification of results against the original 1970s design calculations, providing a clear benchmark for the reliability of historical digital tools in modern structural assessments. 5. Structural analysis software: continuous beams and RC sections The computational core of the simulated design relies on the original routines provided in the HP Civil Engineering Pac (Hewlett-packard, 1977), specifically designed for the HP 67 and HP 97 platforms. For the longitudinal analysis of the bridge, which consists of a symmetrical two-span continuous beam, the program CE1-15A (See Fig. 4 - Six Span Continuous Beams) was selected to solve for the intermediate moments across the support points. This program utilizes an iterative procedure based on the three-moment equation to ensure convergence of the internal couples. A key operational step involves the preliminary determination of the slope factors - representing the kinematic rotations at the supports - calculated by breaking the continuous beam into independent segments and applying the simply supported beam routines CE-09 or CE-10.

Fig. 4. CE1-15A Magnetic card software for Hp67/97 Calculators Following the global analysis, the verification of the reinforced concrete members is conducted using the CE1-17A program (Reinforced Concrete Beams). This routine follows the strength design method of the ACI 318-71 code and allows for the interchangeable solution of six key variables, including the area of tension reinforcement, internal bending moment, and section geometry. The software is particularly suited for the analysis of the bridge's main girders, as it can model T-beams by verifying if the neutral axis depth remains within the slab thickness. Furthermore, the program includes automated checks for minimum and maximum reinforcement ratios, providing a flashing display warning if code specifications are not met. By integrating these historical programs within the Limpid Fox simulator, the design process generates a traceable output that replicates the original thermal printer tapes, ensuring a rigorous comparison with the historical 1970s documentation.