protected override TCIterationBound GetSolutionBoundaries(SectionAnalysisResult result, LinearStrainDistribution ApproximationStrainDistribution) { double prestressForce = this.GetPrestressForceEffective(); if (prestressForce == 0) { //TODO: add check for prstressing if needed //throw new NotPrestressedBeamException(); } //prestressed beam strain iteration is different (from regular RC) from regular concrete because we are assuming that //the maximum depth of compression zone is 0.6d. Therefore this determines the start of iterations TCIterationBound bound = new TCIterationBound(); switch (currentCompressionFiberPosition) { case FlexuralCompressionFiberPosition.Top: bound.MinStrain = ApproximationStrainDistribution.BottomFiberStrain; break; case FlexuralCompressionFiberPosition.Bottom: bound.MinStrain = ApproximationStrainDistribution.TopFiberStrain; break; default: throw new CompressionFiberPositionException(); } bound.MaxStrain = CalculateMaximumSteelStrain(currentCompressionFiberPosition); return(bound); }
protected virtual TCIterationBound GetSolutionBoundaries(SectionAnalysisResult result, LinearStrainDistribution ApproximationStrainDistribution) { double t = Math.Abs(result.TForce); double c = Math.Abs(result.CForce); SectionAnalysisResult secondResult = new SectionAnalysisResult(); TCIterationBound data = new TCIterationBound(); LinearStrainDistribution secondApproximationStrainDistribution = null; double MaxSteelStrain = CalculateMaximumSteelStrain(currentCompressionFiberPosition); //Step 1: create adjusted strain distribution if (t > c) { if (currentCompressionFiberPosition == FlexuralCompressionFiberPosition.Top) { secondApproximationStrainDistribution = new LinearStrainDistribution(ApproximationStrainDistribution.Height, ApproximationStrainDistribution.TopFiberStrain, this.MaxConcreteStrain); } else { secondApproximationStrainDistribution = new LinearStrainDistribution(ApproximationStrainDistribution.Height, this.MaxConcreteStrain, ApproximationStrainDistribution.BottomFiberStrain); } } else { if (currentCompressionFiberPosition == FlexuralCompressionFiberPosition.Top) { secondApproximationStrainDistribution = new LinearStrainDistribution(ApproximationStrainDistribution.Height, ApproximationStrainDistribution.TopFiberStrain, MaxSteelStrain); } else { secondApproximationStrainDistribution = new LinearStrainDistribution(ApproximationStrainDistribution.Height, MaxSteelStrain, ApproximationStrainDistribution.BottomFiberStrain); } } //Step 2: Fill in data for output if (currentCompressionFiberPosition == FlexuralCompressionFiberPosition.Top) { data.MinStrain = -Math.Max(Math.Abs(ApproximationStrainDistribution.BottomFiberStrain), Math.Abs(secondApproximationStrainDistribution.BottomFiberStrain)); data.MaxStrain = -Math.Min(Math.Abs(ApproximationStrainDistribution.BottomFiberStrain), Math.Abs(secondApproximationStrainDistribution.BottomFiberStrain)); } else { data.MinStrain = -Math.Max(Math.Abs(ApproximationStrainDistribution.TopFiberStrain), Math.Abs(secondApproximationStrainDistribution.TopFiberStrain)); data.MaxStrain = -Math.Min(Math.Abs(ApproximationStrainDistribution.TopFiberStrain), Math.Abs(secondApproximationStrainDistribution.TopFiberStrain)); } return(data); }
protected virtual SectionAnalysisResult FindPureMomentResult(FlexuralCompressionFiberPosition CompressionFiberPosition, TCIterationBound bound, double StrainConvergenceTolerance = 0.00001) { currentCompressionFiberPosition = CompressionFiberPosition; //store this off because it will be necessary during iteration StrainHeight = GetStrainDistributionHeight(CompressionFiberPosition); //store this off because it will be necessary during iteration double SteelStrain = 0; double StrainMax = bound.MaxStrain; double StrainMin = bound.MinStrain; double targetTCDelta = 0; LinearStrainDistribution finalStrainDistribution = null; //SteelStrain = RootFinding.Brent(new FunctionOfOneVariable(GetTandCDeltaForSteelStrainIteration), TCDeltaMin, TCDeltaMax, StrainConvergenceTolerance, targetTCDelta); SteelStrain = RootFinding.Brent(new FunctionOfOneVariable(DeltaTCCalculationFunction), StrainMin, StrainMax, StrainConvergenceTolerance, targetTCDelta); switch (CompressionFiberPosition) { case FlexuralCompressionFiberPosition.Top: finalStrainDistribution = new LinearStrainDistribution(StrainHeight, this.MaxConcreteStrain, SteelStrain); break; case FlexuralCompressionFiberPosition.Bottom: finalStrainDistribution = new LinearStrainDistribution(StrainHeight, SteelStrain, this.MaxConcreteStrain); break; default: throw new CompressionFiberPositionException(); } SectionAnalysisResult finalResult = GetSectionResult(finalStrainDistribution, CompressionFiberPosition); return(finalResult); }
public IStrainCompatibilityAnalysisResult GetNominalFlexuralCapacity (FlexuralCompressionFiberPosition CompressionFiberPosition) { currentCompressionFiberPosition = CompressionFiberPosition; //Step 1: Assume strain distribution with all bars below section centroid yielding LinearStrainDistribution TrialStrainDistribution = GetInitialStrainEstimate(CompressionFiberPosition); SectionAnalysisResult TrialSectionResult = GetSectionResult(TrialStrainDistribution, CompressionFiberPosition); double Mn = 0; //check id T and C force are equal //if T<>C if (GetAnalysisResultConverged(TrialSectionResult, ConvergenceToleranceStrain) == false) { SectionAnalysisResult IteratedResult = null; try { TCIterationBound bound = GetSolutionBoundaries(TrialSectionResult, TrialStrainDistribution); //make sure solution exists IteratedResult = FindPureMomentResult(CompressionFiberPosition, bound, ConvergenceToleranceStrain); RebarPointResult controllingBar = GetMaxSteelStrainPoint(TrialSectionResult.TensionRebarResults); Mn = IteratedResult.Moment; return(new ConcreteSectionFlexuralAnalysisResult(Mn, IteratedResult.StrainDistribution, controllingBar)); } catch (SectionAnalysisFailedToConvergeException) { throw new SectionFailedToConvergeException(); } } //if T=C else { IStrainCompatibilityAnalysisResult result = GetResult(TrialSectionResult); return(result); } }