Judgment, Supreme Court, Bronx County (David Levy, J.), entered October 15, 1992, upon a jury verdict in favor of defendant New York City Housing Authority dismissing the complaint in an action for personal injury, affirmed, without costs.
The lower court properly exercised its discretion in excluding plaintiff’s expert testimony and documentary evidence as to the allegedly defective sloping stair. Not only was this claim not alleged in the notice of claim, not mentioned in the complaint, and not set forth in the bill of particulars, but the evidence did not establish that the slope of the stair caused the fall. Plaintiff had no recollection of exactly how the *417accident occurred, and plaintiff’s expert and counsel both conceded that the accident would have occurred whether or not the stair was slanted.
Nor did the trial court err when it permitted defendant’s expert to offer demonstrative testimony regarding the courthouse stairs. Demonstrative evidence is not per se prejudicial and the determination as to its appropriateness lies in the sound discretion of the trial court (see, Harvey v Mazal Am. Partners, 179 AD2d 1, 6-9). Defense was free to introduce evidence of common practice and usage as long as a proper foundation was established (see, Trimarco v Klein, 56 NY2d 98, 106-108). At any rate, when this evidence was introduced, plaintiff objected only to its relevance, not to any alleged prejudicial impact, and did not object to defense counsel’s comments on this issue at summation or request a precautionary instruction to the jury. Concur—Murphy, P. J., Rubin and Williams, JJ.