Moisture Preparation and Bending Performance of Metal Plate Connected C24 Spruce Members in an Exploratory Comparison of Two Connector Systems

Moisture preparation, moisture at testing, and timber variability can jointly influence the response of metal-plate-connected (MPC) members. This exploratory re-analysis concerns 18 C24 Norway spruce assemblies (45 × 170 mm) with Mitek T150 or Ristek LL13 plates. The principal comparison includes 14 directly conditioned specimens in nominal 15%, 20%, and 40% preparation groups, with only two or three beams per connector–group cell; four moisture-transition specimens are described separately. Pooled mean ultimate loads were 14.15, 11.41, and 10.22 kN, respectively. An additive model summarized a nominal-group association (F(2,10) ≈ 12.29, p ≈ 0.002; bias-reduced, nonpartial ω2 ≈ 0.587), but this estimate remains uncertain in such a small sample. The connector comparison was inconclusive (p ≈ 0.122), rather than evidence of equivalent performance. In the nominal 40% group, reported mean moisture differed substantially between Mitek and Ristek (40.45% and 26.35%), and resistance-meter readings in the wet range lack documented validation. Separate verified moisture records at pressing and testing, and the timber-allocation procedure, are not documented. Consequently, preparation history, test-state moisture, connector system, and possible timber-batch differences cannot be separated causally. Laboratory coupons were summarized at the parent-beam level, without treating subsamples as independent treatment replicates. The findings identify associations requiring a balanced, replicated experiment; they do not establish an assembly-moisture effect, a connector ranking, or a design reduction factor.