Geosynthetic Seam Strength
Calculate the strength of a geosynthetic seam (sewn or welded), T_seam = (E ÷ 100)·T_ult, from the seam efficiency E (% of base material strength) and the geosynthetic ultimate strength T_ult (kN/m). Geosynthetics come in limited-width rolls, and on large works (reinforced walls, embankments, geomembrane-lined ponds) must be SEAMED to cover the whole area — by sewing, thermal welding (geomembranes) or simple overlap. The seam is almost always the WEAKEST POINT of the system: a sewn seam has efficiency typically 50-80% of the base fabric strength (the needle punctures and weakens the material, and the thread can be the weak link), while well-made thermal welds in geomembranes can reach 80-100%. So in REINFORCEMENT geosynthetics, seams perpendicular to the main tension are avoided or reinforced, and in barrier geomembranes (landfills, ponds) welds are rigorously tested (dual-channel air pressure, vacuum, destructive tests), since a leak from a bad seam compromises the whole lining. Knowing the seam strength is essential for design and quality control. Enter the seam efficiency and the ultimate strength.
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Resistência de emenda de geossintético
A resistência de uma emenda (costura ou solda) de geossintético é T_emenda = (E ÷ 100)·T_ult, a partir da eficiência da emenda E (% da resistência do material base) e da resistência última T_ult. Geossintéticos vêm em rolos de largura limitada, e em obras grandes (muros reforçados, aterros, lagoas com geomembrana) precisam ser emendados para cobrir toda a área — por costura, solda térmica (geomembranas) ou simples sobreposição. A emenda é quase sempre o ponto mais fraco do sistema: uma costura tem eficiência tipicamente de 50 a 80% da resistência do tecido base (a agulha perfura e enfraquece o material, e a linha pode ser o elo fraco), enquanto soldas térmicas bem executadas em geomembranas chegam a 80-100%. Por isso, em geossintéticos de reforço, as emendas perpendiculares à direção da tração principal são evitadas ou reforçadas; e em geomembranas de barreira (aterros sanitários, lagoas, tanques), as soldas são rigorosamente testadas (pressão de ar no canal duplo, vácuo, ensaios destrutivos), pois um vazamento por emenda mal feita compromete toda a impermeabilização — com consequências ambientais graves. Conhecer a resistência da emenda é essencial para o projeto estrutural e para o controle de qualidade da instalação. Informe a eficiência da emenda e a resistência última.
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Skip Distance (Angle-Beam Ultrasonics)
Computes the skip distance of an angle-beam ultrasonic test, S = 2 × t × tan(θ), the surface distance between the beam entry point and the point where it returns to that same surface after bouncing off the back wall. It is what sets the operator's scanning band: to cover the full thickness of a butt weld the probe must sweep between half a skip (t × tan θ, where the beam reaches the back wall) and a full skip. Larger angles stretch the skip and move the probe away from the bead, which helps when the weld cap cannot be ground off, but they also lengthen the sound path and increase attenuation. Enter the part thickness and the probe refracted angle.
Allowable Geosynthetic Strength
Calculate the allowable (design) tensile strength of a geosynthetic, T_adm = T_ult ÷ (RF_cr·RF_id·RF_cd), from the ultimate strength T_ult (kN/m, from a short-term tensile test) and the reduction factors for creep RF_cr, installation damage RF_id and chemical/biological degradation RF_cd. Geosynthetics (geotextiles, geogrids, geomembranes) used as soil REINFORCEMENT in walls, slopes and embankments on soft soils must work for decades, and their design strength is far below the lab value from quick tests. The reduction factors discount: CREEP (polymers under constant load deform and lose strength over time, RF_cr typically 2-5, the largest factor); INSTALLATION DAMAGE (compacting gravel fill over the geosynthetic causes abrasion and punctures, RF_id ~1.1-2); and chemical/biological DEGRADATION over the service life (RF_cd ~1.1-2). Their product can reduce the allowable strength to 20-40% of the ultimate. This is the basis of designing any reinforced-soil structure, and underestimating the reduction factors (overestimating strength) is a cause of reinforced wall and slope failures. Enter the ultimate strength and the three reduction factors.
One-Sample Variance Test (Chi-Square)
Computes the chi-square test for the variance of a single sample, which checks whether the population variance equals a reference value. It's the dispersion counterpart of the one-sample t-test for the mean. It shows up often in quality control: is a process's variability within the specified limit, or has it increased? The statistic compares the sample variance with the hypothesized one and follows a chi-square distribution. Enter the sample and the hypothesized variance (σ₀²).
Fillet Weld Throat
Calculate the effective throat of a fillet weld, a = 0.707 × z, from the leg z of the fillet. For an equal-leg fillet, the throat — the smallest dimension of the resisting section, from root to face — equals the leg times sin(45°) ≈ 0.707. The result, in the same unit as the leg (mm), is the dimension used to calculate the strength of the welded joint, since the weld tends to fail across this minimum section. Sizing the throat correctly ensures the weld carries the design load. Enter the fillet leg.
Geotextile Transmissivity
Calculate a geosynthetic's transmissivity, θ = k_p·t, from the in-plane permeability k_p (m/s) and the thickness t (m); the result, in m²/s, is the transmissivity. Transmissivity characterizes the geosynthetic's ability to convey water WITHIN its own plane (longitudinally, like a planar drain), and is the key property in the DRAINAGE function. While permittivity measures flow THROUGH the geotextile (perpendicular), transmissivity measures flow ALONG it (parallel). It is the fundamental property of drainage geocomposites and geonets — products with a 3D open core (geonet) between filtering geotextiles, used to drain water replacing gravel layers: drainage behind retaining walls, under landfills (leachate and gas collection), in roads, sports fields and gardens (subsurface drainage), and in foundations. Transmissivity depends strongly on confining PRESSURE (the more compressed, the less space for water to flow and the lower θ) and on gradient, so it is specified at the work's real load conditions. Times the gradient and width, it gives the drained flow. Enter the in-plane permeability and the thickness.
Box Compression Strength (McKee)
Estimates the vertical compression strength of a corrugated box with the simplified McKee formula, BCT = 5.87 × ECT × √(board caliper × box perimeter), where ECT — the edge crush resistance measured per TAPPI T 811 (ISO 3037) — is in newtons per millimetre and both dimensions are in millimetres. The result, in newtons, is the load an empty box withstands in the laboratory compression test, with the board conditioned at 23 °C and 50% relative humidity. Because strength grows with the square root of the perimeter and linearly with ECT, doubling the perimeter buys only 41% more, while switching to a flute with 30% higher ECT buys the full 30% — upgrading the board usually beats reshaping the box. For real pallet stacking, divide the BCT by a safety factor of 3 to 5, which covers the stiffness lost to ambient humidity, the creep of board under load over weeks and the misalignment between boxes in the column. Enter the ECT, the board caliper and the box perimeter.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.